From e468b08fb718f05b2f054716e5b4a40441fa7b7a Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Sat, 19 Sep 2026 05:33:10 +0200
Subject: [PATCH 01/23] feat: enable push notifications for several accounts at
 once

The notification panel only ever addresses the account on screen, so
arming a browser for five accounts meant switching account five times
and answering the same permission prompt on each pass.

The browser holds a single push subscription: enabling an account
registers it against that one subscription rather than creating another.
A section in the notification settings now lists every connected account
with its current state and turns push on or off for the ones selected,
walking them against the same subscription.

A refusal at the browser level - unsupported, or permission denied -
applies to every account, so it stops the walk instead of failing each
account in turn and prompting repeatedly.
---
 components/settings/multi-account-push.tsx    | 111 ++++++++++++++++++
 components/settings/notification-settings.tsx |   3 +
 lib/__tests__/web-push.test.ts                |  38 ++++++
 lib/web-push.ts                               |  51 ++++++++
 locales/ar/common.json                        |  12 ++
 locales/ca/common.json                        |  12 ++
 locales/cs/common.json                        |  12 ++
 locales/da/common.json                        |  12 ++
 locales/de/common.json                        |  12 ++
 locales/en/common.json                        |  12 ++
 locales/es/common.json                        |  12 ++
 locales/fa/common.json                        |  12 ++
 locales/fr/common.json                        |  12 ++
 locales/he/common.json                        |  12 ++
 locales/hu/common.json                        |  12 ++
 locales/it/common.json                        |  12 ++
 locales/ja/common.json                        |  12 ++
 locales/ko/common.json                        |  12 ++
 locales/lv/common.json                        |  12 ++
 locales/mn/common.json                        |  12 ++
 locales/nb/common.json                        |  12 ++
 locales/nl/common.json                        |  12 ++
 locales/pl/common.json                        |  12 ++
 locales/pt/common.json                        |  12 ++
 locales/ro/common.json                        |  12 ++
 locales/ru/common.json                        |  12 ++
 locales/sk/common.json                        |  12 ++
 locales/tr/common.json                        |  12 ++
 locales/uk/common.json                        |  12 ++
 locales/zh-TW/common.json                     |  12 ++
 locales/zh/common.json                        |  12 ++
 31 files changed, 527 insertions(+)
 create mode 100644 components/settings/multi-account-push.tsx

diff --git a/components/settings/multi-account-push.tsx b/components/settings/multi-account-push.tsx
new file mode 100644
index 000000000..fb0038d20
--- /dev/null
+++ b/components/settings/multi-account-push.tsx
@@ -0,0 +1,111 @@
+'use client';
+
+import { useCallback, useEffect, useState } from 'react';
+import { useTranslations } from 'next-intl';
+import { Loader2 } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { SettingsSection } from './settings-section';
+import { useAccountStore } from '@/stores/account-store';
+import { useAuthStore } from '@/stores/auth-store';
+import { disableWebPush, enableWebPushForAccounts, isWebPushEnabled, isWebPushSupported } from '@/lib/web-push';
+
+/**
+ * Turn push on or off for several accounts at once.
+ *
+ * The per-account panel above only ever addresses the account on screen, so
+ * arming a fresh device used to mean switching account N times. One browser
+ * subscription already serves every account (see `enableWebPushForAccounts`);
+ * what was missing was a place to register them all against it in one go.
+ */
+export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: string }) {
+  const t = useTranslations('settings.notifications.push_all');
+  const accounts = useAccountStore(s => s.accounts);
+  // Re-read the client map whenever a connection appears or drops.
+  const revision = useAuthStore(s => s.connectedAccountsRevision);
+  const [enabled, setEnabled] = useState<Record<string, boolean>>({});
+  const [chosen, setChosen] = useState<Set<string>>(new Set());
+  const [busy, setBusy] = useState(false);
+  const [notice, setNotice] = useState('');
+
+  const connected = accounts.filter(a => a.isConnected && useAuthStore.getState().getClientForAccount(a.id));
+
+  const refresh = useCallback(async () => {
+    const entries = await Promise.all(
+      useAccountStore.getState().accounts.map(async a => [a.id, await isWebPushEnabled(a.id)] as const),
+    );
+    setEnabled(Object.fromEntries(entries));
+  }, []);
+
+  useEffect(() => { void refresh(); }, [refresh, revision]);
+
+  if (!isWebPushSupported() || connected.length < 2) return null;
+
+  const toggle = (id: string, on: boolean) => setChosen(prev => {
+    const next = new Set(prev);
+    if (on) next.add(id); else next.delete(id);
+    return next;
+  });
+
+  const run = async (action: 'enable' | 'disable') => {
+    const auth = useAuthStore.getState();
+    const targets = connected.filter(a => chosen.has(a.id));
+    if (!targets.length) return;
+    setBusy(true); setNotice('');
+    try {
+      if (action === 'enable') {
+        const outcome = await enableWebPushForAccounts(
+          targets.map(a => ({ accountId: a.id, client: auth.getClientForAccount(a.id)!, accountLabel: a.username })),
+          { relayBaseUrl },
+        );
+        setNotice(outcome.failed.length
+          ? t('result_partial', { enabled: outcome.enabled.length, failed: outcome.failed.length })
+          : t('result_enabled', { count: outcome.enabled.length }));
+      } else {
+        // Teardown swallows its own failures, so every account ends up local-off.
+        for (const account of targets) {
+          await disableWebPush({ client: auth.getClientForAccount(account.id)!, relayBaseUrl });
+        }
+        setNotice(t('result_disabled', { count: targets.length }));
+      }
+      setChosen(new Set());
+    } finally {
+      setBusy(false);
+      await refresh();
+    }
+  };
+
+  const allChosen = connected.length > 0 && connected.every(a => chosen.has(a.id));
+
+  return <SettingsSection title={t('title')} description={t('description')}>
+    <div className="space-y-3">
+      <label className="flex items-center gap-2 text-sm font-medium">
+        <input type="checkbox" disabled={busy} checked={allChosen}
+          onChange={e => setChosen(e.target.checked ? new Set(connected.map(a => a.id)) : new Set())} />
+        {t('select_all')}
+      </label>
+      <ul className="space-y-2">
+        {connected.map(account => <li key={account.id}>
+          <label className="flex items-start gap-2 pl-6 text-sm">
+            <input type="checkbox" className="mt-1" disabled={busy} checked={chosen.has(account.id)}
+              onChange={e => toggle(account.id, e.target.checked)} />
+            <span>
+              <span className="block">{account.displayName || account.label || account.username}</span>
+              <span className="block text-xs text-muted-foreground">
+                {account.email || account.username} · {enabled[account.id] ? t('state_on') : t('state_off')}
+              </span>
+            </span>
+          </label>
+        </li>)}
+      </ul>
+      <div className="flex flex-wrap items-center gap-2">
+        <Button type="button" onClick={() => void run('enable')} disabled={busy || !chosen.size}>
+          {busy && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}{t('enable_selected')}
+        </Button>
+        <Button type="button" variant="outline" onClick={() => void run('disable')} disabled={busy || !chosen.size}>
+          {t('disable_selected')}
+        </Button>
+      </div>
+      {notice && <p className="text-sm text-muted-foreground">{notice}</p>}
+    </div>
+  </SettingsSection>;
+}
diff --git a/components/settings/notification-settings.tsx b/components/settings/notification-settings.tsx
index 2864b3958..3170c8007 100644
--- a/components/settings/notification-settings.tsx
+++ b/components/settings/notification-settings.tsx
@@ -11,6 +11,7 @@ import { Loader2, RefreshCw, Volume2, XCircle } from 'lucide-react';
 import { usePolicyStore } from '@/stores/policy-store';
 import { useAuthStore } from '@/stores/auth-store';
 import { ConfirmDialog } from '@/components/ui/confirm-dialog';
+import { MultiAccountPushSettings } from './multi-account-push';
 import { useConfirmDialog } from '@/hooks/use-confirm-dialog';
 import {
   WebPushUnsupportedError,
@@ -251,6 +252,8 @@ export function NotificationSettings() {
         )}
       </SettingsSection>
 
+      <MultiAccountPushSettings relayBaseUrl={activeRelayUrl} />
+
       {client && (
         <SettingsSection title={t('push.devices_title')} description={t('push.devices_desc')}>
           <div className="flex items-center justify-between gap-2">
diff --git a/lib/__tests__/web-push.test.ts b/lib/__tests__/web-push.test.ts
index 369266b2a..02fc80183 100644
--- a/lib/__tests__/web-push.test.ts
+++ b/lib/__tests__/web-push.test.ts
@@ -4,6 +4,7 @@ import type { EmailPushConfig, PushSubscription as JmapPushSubscription } from '
 import {
   disableWebPush,
   enableWebPush,
+  enableWebPushForAccounts,
   listPushDevices,
   resetWebPushResyncState,
   resyncWebPush,
@@ -454,3 +455,40 @@ describe('revokePushDevice', () => {
     expect(localStorage.getItem(SUB_KEY)).toBeNull();
   });
 });
+
+describe('enableWebPushForAccounts', () => {
+  it('registers every account against the one browser subscription', async () => {
+    const first = makeClient([]);
+    const second = makeClient([]);
+    installFetch({});
+
+    const result = await enableWebPushForAccounts([
+      { accountId: 'a', client: first, accountLabel: 'one' },
+      { accountId: 'b', client: second, accountLabel: 'two' },
+    ], { relayBaseUrl: RELAY });
+
+    expect(result.enabled).toEqual(['a', 'b']);
+    expect(result.failed).toEqual([]);
+    expect(first.createPushSubscription).toHaveBeenCalledTimes(1);
+    expect(second.createPushSubscription).toHaveBeenCalledTimes(1);
+  });
+
+  it('stops at a browser-level refusal instead of prompting once per account', async () => {
+    const first = makeClient([]);
+    const second = makeClient([]);
+    installFetch({});
+    // Blocked notifications are a property of the browser, not of an account:
+    // walking on would fail identically for every one of them.
+    (globalThis as unknown as { Notification: unknown }).Notification = { permission: 'denied' };
+    (window as unknown as { Notification: unknown }).Notification = { permission: 'denied' };
+
+    const result = await enableWebPushForAccounts([
+      { accountId: 'a', client: first },
+      { accountId: 'b', client: second },
+    ], { relayBaseUrl: RELAY });
+
+    expect(result.enabled).toEqual([]);
+    expect(result.failed.map(f => f.accountId)).toEqual(['a', 'b']);
+    expect(second.createPushSubscription).not.toHaveBeenCalled();
+  });
+});
diff --git a/lib/web-push.ts b/lib/web-push.ts
index 973e1cd5f..ad4ab123d 100644
--- a/lib/web-push.ts
+++ b/lib/web-push.ts
@@ -695,3 +695,54 @@ export async function resyncWebPush(params: ResyncWebPushParams): Promise<boolea
 export function resetWebPushResyncState(): void {
   resyncedAccountIds.clear();
 }
+
+export interface BulkWebPushTarget {
+  accountId: string;
+  client: IJMAPClient;
+  accountLabel?: string;
+}
+
+export interface BulkWebPushResult {
+  enabled: string[];
+  /** Accounts left untouched, with the reason the first failure gave. */
+  failed: Array<{ accountId: string; error: unknown }>;
+}
+
+/**
+ * Enable push for several accounts against one browser subscription.
+ *
+ * The browser only ever holds a single PushSubscription: `enableWebPush` reuses
+ * it and registers one server-side subscription per account, which is why every
+ * account has to be walked separately. Sequential on purpose - the first call
+ * is the one that may prompt for permission, and parallel prompts race.
+ *
+ * A browser-level refusal (unsupported, permission denied or dismissed) applies
+ * to every account, so it stops the walk instead of failing them one by one.
+ */
+export async function enableWebPushForAccounts(
+  targets: BulkWebPushTarget[],
+  options: { relayBaseUrl?: string; forceRecreate?: boolean } = {},
+): Promise<BulkWebPushResult> {
+  const result: BulkWebPushResult = { enabled: [], failed: [] };
+  let browserRefusal: unknown;
+  for (const target of targets) {
+    if (browserRefusal !== undefined) {
+      result.failed.push({ accountId: target.accountId, error: browserRefusal });
+      continue;
+    }
+    try {
+      await enableWebPush({
+        client: target.client,
+        relayBaseUrl: options.relayBaseUrl,
+        accountLabel: target.accountLabel,
+        forceRecreate: options.forceRecreate,
+      });
+      result.enabled.push(target.accountId);
+    } catch (error) {
+      if (error instanceof WebPushUnsupportedError || !isWebPushSupported()
+        || Notification.permission !== 'granted') browserRefusal = error;
+      result.failed.push({ accountId: target.accountId, error });
+    }
+  }
+  return result;
+}
diff --git a/locales/ar/common.json b/locales/ar/common.json
index 53d4bf6d8..40027e47e 100644
--- a/locales/ar/common.json
+++ b/locales/ar/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "سيتوقّف فورًا عن تلقّي الإشعارات في الخلفية. تفعيل الدفع مجددًا على ذلك الجهاز سيسجّله من جديد.",
         "confirm_revoke_message_this": "سيتوقّف هذا الجهاز فورًا عن تلقّي الإشعارات في الخلفية."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "صوت الإشعار",
         "description": "اختر الصوت الذي يُشغَّل للإشعارات",
diff --git a/locales/ca/common.json b/locales/ca/common.json
index 686039db0..0ce9f1c47 100644
--- a/locales/ca/common.json
+++ b/locales/ca/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "Deixarà de rebre notificacions en segon pla immediatament. Si hi tornes a activar les notificacions push, es registrarà de nou.",
         "confirm_revoke_message_this": "Aquest dispositiu deixarà de rebre notificacions en segon pla immediatament."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "So de notificació",
         "description": "Trieu quin so es reprodueix per a les notificacions",
diff --git a/locales/cs/common.json b/locales/cs/common.json
index 5262ee69d..a5f64effd 100644
--- a/locales/cs/common.json
+++ b/locales/cs/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Rychlý",
         "relax": "Relaxační"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Zvuk oznámení",
         "description": "Vyberte zvuk, který se přehraje při oznámení",
diff --git a/locales/da/common.json b/locales/da/common.json
index 09552435b..15560af42 100644
--- a/locales/da/common.json
+++ b/locales/da/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "Den stopper med at modtage baggrundsnotifikationer med det samme. Slår du push til igen på enheden, registreres den på ny.",
         "confirm_revoke_message_this": "Denne enhed stopper med at modtage baggrundsnotifikationer med det samme."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Notifikationslyd",
         "description": "Vælg hvilken lyd der skal afspilles for notifikationer",
diff --git a/locales/de/common.json b/locales/de/common.json
index 2d39bfc03..673beedd9 100644
--- a/locales/de/common.json
+++ b/locales/de/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Schnelle Geste",
         "relax": "Entspannt"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Benachrichtigungston",
         "description": "Wählen Sie den Ton für Benachrichtigungen",
diff --git a/locales/en/common.json b/locales/en/common.json
index 78a509e09..19346029c 100644
--- a/locales/en/common.json
+++ b/locales/en/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "It will stop receiving background notifications immediately. Enabling push again on that device registers it anew.",
         "confirm_revoke_message_this": "This device will stop receiving background notifications immediately."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Notification Sound",
         "description": "Choose which sound to play for notifications",
diff --git a/locales/es/common.json b/locales/es/common.json
index ae2413a7f..85f70d57e 100644
--- a/locales/es/common.json
+++ b/locales/es/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Gesto rápido",
         "relax": "Relajado"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Sonido de notificación",
         "description": "Elige qué sonido reproducir para las notificaciones",
diff --git a/locales/fa/common.json b/locales/fa/common.json
index c454007f8..380af698a 100644
--- a/locales/fa/common.json
+++ b/locales/fa/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "بی‌درنگ دریافت اعلان‌های پس‌زمینه را متوقف می‌کند. با روشن‌کردن دوبارهٔ پوش روی آن دستگاه، دوباره ثبت می‌شود.",
         "confirm_revoke_message_this": "این دستگاه بی‌درنگ دریافت اعلان‌های پس‌زمینه را متوقف می‌کند."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "صدای اعلان",
         "description": "صدای پخش شده برای اعلان‌ها",
diff --git a/locales/fr/common.json b/locales/fr/common.json
index 738fd0b3f..5e1237dce 100644
--- a/locales/fr/common.json
+++ b/locales/fr/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Geste rapide",
         "relax": "Détente"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Son de notification",
         "description": "Choisissez le son à jouer pour les notifications",
diff --git a/locales/he/common.json b/locales/he/common.json
index a03914d4f..4b6432e52 100644
--- a/locales/he/common.json
+++ b/locales/he/common.json
@@ -1109,6 +1109,18 @@
         "swift": "מחווה מהירה",
         "relax": "תירגע"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "צליל התראה",
         "description": "בחר איזה צליל להפעיל עבור התראות",
diff --git a/locales/hu/common.json b/locales/hu/common.json
index d348bccb5..5482d43fe 100644
--- a/locales/hu/common.json
+++ b/locales/hu/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "Azonnal nem kap több háttérértesítést. Ha az eszközön újra bekapcsolja a push értesítéseket, újra regisztrálódik.",
         "confirm_revoke_message_this": "Ez az eszköz azonnal nem kap több háttérértesítést."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Értesítési hang",
         "description": "Válaszd ki az értesítésekhez használt hangot",
diff --git a/locales/it/common.json b/locales/it/common.json
index 30c7ab7af..bbffa0958 100644
--- a/locales/it/common.json
+++ b/locales/it/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Gesto veloce",
         "relax": "Rilassante"
       },
+      "push_all": {
+          "title": "Tutti gli account",
+          "description": "Attiva o disattiva le notifiche per più account in una volta sola. Una sola iscrizione del browser li serve tutti.",
+          "select_all": "Seleziona tutti gli account collegati",
+          "state_on": "notifiche attive",
+          "state_off": "notifiche non attive",
+          "enable_selected": "Attiva per i selezionati",
+          "disable_selected": "Disattiva per i selezionati",
+          "result_enabled": "Notifiche attivate per {count} account.",
+          "result_partial": "Attivate per {enabled} account; {failed} non è stato possibile attivarle.",
+          "result_disabled": "Notifiche disattivate per {count} account."
+        },
       "sound_selection": {
         "title": "Suono di notifica",
         "description": "Scegli quale suono riprodurre per le notifiche",
diff --git a/locales/ja/common.json b/locales/ja/common.json
index c6555f190..bed548ec7 100644
--- a/locales/ja/common.json
+++ b/locales/ja/common.json
@@ -1144,6 +1144,18 @@
         "swift": "スウィフトジェスチャー",
         "relax": "リラックス"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "通知音",
         "description": "通知に使用する音を選択",
diff --git a/locales/ko/common.json b/locales/ko/common.json
index 93f56bda1..52073f6b1 100644
--- a/locales/ko/common.json
+++ b/locales/ko/common.json
@@ -1144,6 +1144,18 @@
         "swift": "빠르게",
         "relax": "차분하게"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "알림음",
         "description": "알림이 올 때 재생할 소리를 선택해 주세요",
diff --git a/locales/lv/common.json b/locales/lv/common.json
index b31dd7047..bdab467b3 100644
--- a/locales/lv/common.json
+++ b/locales/lv/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Ātrs",
         "relax": "Relaksējošs"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Paziņojuma skaņa",
         "description": "Izvēlieties skaņu paziņojumiem",
diff --git a/locales/mn/common.json b/locales/mn/common.json
index 0fc2b17f2..22053f418 100644
--- a/locales/mn/common.json
+++ b/locales/mn/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "Тэр даруй араарх мэдэгдэл хүлээн авахаа болино. Тухайн төхөөрөмж дээр push-ыг дахин асаавал дахин бүртгэгднэ.",
         "confirm_revoke_message_this": "Энэ төхөөрөмж тэр даруй араарх мэдэгдэл хүлээн авахаа болино."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Мэдэгдэлийн дуу",
         "description": "Мэдэгдэл авахын тулд ямар дууг тоглуулахаа сонгоно уу",
diff --git a/locales/nb/common.json b/locales/nb/common.json
index 3648dccfc..555de1f2f 100644
--- a/locales/nb/common.json
+++ b/locales/nb/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "Enheten slutter umiddelbart å motta bakgrunnsvarsler. Hvis pushvarsler aktiveres på nytt på enheten, registreres den på nytt.",
         "confirm_revoke_message_this": "Denne enheten slutter umiddelbart å motta bakgrunnsvarsler."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Varslingslyd",
         "description": "Velg hvilken lyd som skal spilles av for varsler",
diff --git a/locales/nl/common.json b/locales/nl/common.json
index 12e564a77..4b629004b 100644
--- a/locales/nl/common.json
+++ b/locales/nl/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Snel gebaar",
         "relax": "Ontspannen"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Meldingsgeluid",
         "description": "Kies welk geluid wordt afgespeeld voor meldingen",
diff --git a/locales/pl/common.json b/locales/pl/common.json
index e903226ee..cfc7d6dd5 100644
--- a/locales/pl/common.json
+++ b/locales/pl/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Szybki gest",
         "relax": "Relaks"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Dźwięk powiadomienia",
         "description": "Wybierz dźwięk odtwarzany dla powiadomień",
diff --git a/locales/pt/common.json b/locales/pt/common.json
index bb8f8c8fc..d623f1cde 100644
--- a/locales/pt/common.json
+++ b/locales/pt/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Gesto rápido",
         "relax": "Relaxante"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Som de notificação",
         "description": "Escolha qual som reproduzir para notificações",
diff --git a/locales/ro/common.json b/locales/ro/common.json
index 0af8fbf90..f9690457c 100644
--- a/locales/ro/common.json
+++ b/locales/ro/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "Va înceta imediat să primească notificări în fundal. Reactivarea push pe acel dispozitiv îl va înregistra din nou.",
         "confirm_revoke_message_this": "Acest dispozitiv va înceta imediat să primească notificări în fundal."
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Sunet de notificare",
         "description": "Alegeți ce sunet să se redea pentru notificări",
diff --git a/locales/ru/common.json b/locales/ru/common.json
index bd08b879c..fb8648b06 100644
--- a/locales/ru/common.json
+++ b/locales/ru/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Быстрый жест",
         "relax": "Релакс"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Звук уведомления",
         "description": "Выберите звук для уведомлений",
diff --git a/locales/sk/common.json b/locales/sk/common.json
index 2e17b787a..43879446a 100644
--- a/locales/sk/common.json
+++ b/locales/sk/common.json
@@ -1147,6 +1147,18 @@
         "swift": "Rýchly",
         "relax": "Relaxačný"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Zvuk oznámenia",
         "description": "Vyberte zvuk, ktorý sa prehrá pri oznámení",
diff --git a/locales/tr/common.json b/locales/tr/common.json
index f6755de49..4cc0783c1 100644
--- a/locales/tr/common.json
+++ b/locales/tr/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Hızlı Jest",
         "relax": "Rahatla"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Bildirim Sesi",
         "description": "Bildirimler için hangi sesin çalınacağını seçin",
diff --git a/locales/uk/common.json b/locales/uk/common.json
index a896c863c..63d19c065 100644
--- a/locales/uk/common.json
+++ b/locales/uk/common.json
@@ -1144,6 +1144,18 @@
         "swift": "Швидкий жест",
         "relax": "Розслабтеся"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "Звук сповіщення",
         "description": "Виберіть звук для сповіщень",
diff --git a/locales/zh-TW/common.json b/locales/zh-TW/common.json
index 289ce6d53..6f8818fb6 100644
--- a/locales/zh-TW/common.json
+++ b/locales/zh-TW/common.json
@@ -1183,6 +1183,18 @@
         "confirm_revoke_message": "此裝置會立即停止接收背景通知。若在該裝置上再次啟用推送，將重新註冊。",
         "confirm_revoke_message_this": "此裝置會立即停止接收背景通知。"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "通知聲音",
         "description": "選擇通知時播放的聲音",
diff --git a/locales/zh/common.json b/locales/zh/common.json
index 2cf732396..fba5f24d2 100644
--- a/locales/zh/common.json
+++ b/locales/zh/common.json
@@ -1144,6 +1144,18 @@
         "swift": "轻快手势",
         "relax": "放松"
       },
+      "push_all": {
+          "title": "All accounts",
+          "description": "Turn push on or off for several accounts at once. One browser subscription serves them all.",
+          "select_all": "Select every connected account",
+          "state_on": "notifications on",
+          "state_off": "notifications off",
+          "enable_selected": "Enable for selected",
+          "disable_selected": "Disable for selected",
+          "result_enabled": "Notifications enabled for {count} accounts.",
+          "result_partial": "Enabled for {enabled} accounts; {failed} could not be enabled.",
+          "result_disabled": "Notifications disabled for {count} accounts."
+        },
       "sound_selection": {
         "title": "通知声音",
         "description": "选择通知时播放的声音",

From fac3bdf31c14eedbb111ddce0a29d46c074b9846 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Sat, 19 Sep 2026 08:59:21 +0200
Subject: [PATCH 02/23] fix: scope batch selection to the owning account

Email ids are unique only within their account, so in a view that merges
several - the unified mailbox, and since #1038 the tag view - two
unrelated messages can share one. Selection was a set of bare ids
resolved with `emails.filter(e => selected.has(e.id))`, so ticking one
row also ticked its namesake in another account, and batch delete, move,
archive or mark-read then acted on a message nobody selected.

Reported by @alyyousuf7 on #1013, where `eiaaaabc` exists in two
accounts at once.

Selection is now keyed by `emailKeyFor` - the same account scoping
#1013 introduced for threads - and the actions take the email rather
than its id, so a caller cannot reintroduce the collision by passing a
bare id. Unstamped emails keep the bare id as their key, so
single-account views are unchanged.

The batch actions derive the JMAP ids from the selected emails
themselves instead of looking each id up again, which is where the
namesake used to ride along, and every place that pruned the selection
after a delete or a move now prunes by key.
---
 .../email/__tests__/thread-list-item.test.tsx |  14 +-
 components/email/email-list.tsx               |  20 +-
 components/email/thread-email-item.tsx        |  14 +-
 components/email/thread-list-item.tsx         |  36 ++--
 components/mail/mail-app.tsx                  |  42 ++--
 hooks/use-email-drag.ts                       |  16 +-
 hooks/use-mailbox-drop.ts                     |   6 +-
 lib/__tests__/account-state-manager.test.ts   |   4 +-
 lib/account-state-manager.ts                  |   2 +-
 lib/thread-utils.ts                           |  17 ++
 stores/__tests__/email-archive.test.ts        |   4 +-
 .../email-selection-cross-account.test.ts     |  62 ++++++
 stores/__tests__/email-selection.test.ts      |  62 +++---
 .../email-store-archive-missing.test.ts       |   4 +-
 .../email-store-multi-account.test.ts         |   6 +-
 .../email-store-retained-in-view.test.ts      |   4 +-
 .../email-store-shared-folder-actions.test.ts |   4 +-
 ...email-store-shared-folder-keywords.test.ts |   2 +-
 .../__tests__/email-store-tag-counts.test.ts  |   4 +-
 .../email-store-tag-view-accounts.test.ts     |   6 +-
 .../email-store-unified-actions.test.ts       |  16 +-
 stores/email-store.ts                         | 183 ++++++++++--------
 22 files changed, 325 insertions(+), 203 deletions(-)
 create mode 100644 stores/__tests__/email-selection-cross-account.test.ts

diff --git a/components/email/__tests__/thread-list-item.test.tsx b/components/email/__tests__/thread-list-item.test.tsx
index f9b312e39..4b3f6d249 100644
--- a/components/email/__tests__/thread-list-item.test.tsx
+++ b/components/email/__tests__/thread-list-item.test.tsx
@@ -53,7 +53,7 @@ describe('ThreadListItem tag badge', () => {
       mailLayout: 'split',
     });
     useEmailStore.setState({
-      selectedEmailIds: new Set<string>(),
+      selectedEmailKeys: new Set<string>(),
       selectedMailbox: 'inbox',
     });
   });
@@ -126,7 +126,7 @@ describe('ThreadListItem multi-message thread', () => {
       mailLayout: 'split',
     });
     useEmailStore.setState({
-      selectedEmailIds: new Set<string>(),
+      selectedEmailKeys: new Set<string>(),
       selectedMailbox: 'inbox',
     });
   });
@@ -187,7 +187,7 @@ describe('ThreadListItem row content', () => {
       mailLayout: 'split',
     });
     useEmailStore.setState({
-      selectedEmailIds: new Set<string>(),
+      selectedEmailKeys: new Set<string>(),
       selectedMailbox: 'inbox',
     });
   });
@@ -226,8 +226,8 @@ describe('ThreadListItem shift-range avatar selection', () => {
     // Selection mode active, with the anchor on e1.
     useEmailStore.setState({
       emails: [e1, e2, e3],
-      selectedEmailIds: new Set(['e1']),
-      lastSelectedEmailId: 'e1',
+      selectedEmailKeys: new Set(['e1']),
+      lastSelectedEmailKey: 'e1',
       selectedMailbox: 'inbox',
     });
 
@@ -237,7 +237,7 @@ describe('ThreadListItem shift-range avatar selection', () => {
       avatar.dispatchEvent(new MouseEvent('click', { bubbles: true, shiftKey: true }));
     });
 
-    const selected = useEmailStore.getState().selectedEmailIds;
+    const selected = useEmailStore.getState().selectedEmailKeys;
     expect(selected.has('e1')).toBe(true);
     expect(selected.has('e2')).toBe(true); // the row in between got filled in
     expect(selected.has('e3')).toBe(true);
@@ -256,7 +256,7 @@ describe('ThreadListItem row tint', () => {
       tintListRowsByTag: true,
     });
     useEmailStore.setState({
-      selectedEmailIds: new Set(['email-1']),
+      selectedEmailKeys: new Set(['email-1']),
       selectedMailbox: 'inbox',
     });
   });
diff --git a/components/email/email-list.tsx b/components/email/email-list.tsx
index 71ef9e256..37bb72a15 100644
--- a/components/email/email-list.tsx
+++ b/components/email/email-list.tsx
@@ -88,7 +88,7 @@ export function EmailList({
   const tSpam = useTranslations('email_viewer.spam');
   const { client } = useAuthStore();
   const {
-    selectedEmailIds,
+    selectedEmailKeys,
     selectAllEmails: _selectAllEmails,
     clearSelection,
     batchMarkAsRead,
@@ -227,7 +227,7 @@ export function EmailList({
     </div>
   );
 
-  const hasSelection = selectedEmailIds.size > 0;
+  const hasSelection = selectedEmailKeys.size > 0;
 
   const handleBatchMarkAsRead = async (read: boolean) => {
     if (!client || isProcessing) return;
@@ -243,7 +243,7 @@ export function EmailList({
     if (!client || isProcessing) return;
     setIsProcessing(true);
     try {
-      const emailIds = Array.from(selectedEmailIds);
+      const emailIds = Array.from(selectedEmailKeys);
       await batchUndoSpam(client, emailIds);
       const { toast } = await import('sonner');
       toast.success(tSpam('toast_not_spam_batch', { count: emailIds.length }));
@@ -266,8 +266,8 @@ export function EmailList({
         ? t('permanent_delete_confirm_title')
         : t('batch_actions.delete_confirm_title'),
       message: isInTrash
-        ? t('permanent_delete_confirm_batch_message', { count: selectedEmailIds.size })
-        : t('batch_actions.delete_confirm_message', { count: selectedEmailIds.size }),
+        ? t('permanent_delete_confirm_batch_message', { count: selectedEmailKeys.size })
+        : t('batch_actions.delete_confirm_message', { count: selectedEmailKeys.size }),
       confirmText: isInTrash
         ? t('permanent_delete')
         : t('batch_actions.delete'),
@@ -391,7 +391,7 @@ export function EmailList({
         <div className="px-4 py-2 border-b bg-accent/30 border-border flex items-center justify-between">
           <div className="flex items-center gap-2 animate-in fade-in slide-in-from-left-3 duration-300">
             <span className="text-sm font-medium text-foreground">
-              {t('batch_actions.selected_messages', { count: selectedEmailIds.size })}
+              {t('batch_actions.selected_messages', { count: selectedEmailKeys.size })}
             </span>
           </div>
           <div className="flex items-center gap-1 animate-in fade-in slide-in-from-right-3 duration-300">
@@ -629,8 +629,8 @@ export function EmailList({
           mailboxes={mailboxes}
           selectedMailbox={selectedMailbox}
           currentMailboxRole={effectiveMailboxRole}
-          isMultiSelect={selectedEmailIds.has(contextMenuEmail.id)}
-          selectedCount={selectedEmailIds.size}
+          isMultiSelect={selectedEmailKeys.has(contextMenuEmail.id)}
+          selectedCount={selectedEmailKeys.size}
           onReply={() => onReply?.(contextMenuEmail!)}
           onReplyAll={() => onReplyAll?.(contextMenuEmail!)}
           onForward={() => onForward?.(contextMenuEmail!)}
@@ -660,7 +660,7 @@ export function EmailList({
           onBatchMoveToMailbox={(mailboxId) => client && batchMoveToMailbox(client, mailboxId)}
           onBatchMarkAsSpam={async () => {
             if (client) {
-              const emailIds = Array.from(selectedEmailIds);
+              const emailIds = Array.from(selectedEmailKeys);
               try {
                 await batchMarkAsSpam(client, emailIds);
                 const { toast } = await import('sonner');
@@ -675,7 +675,7 @@ export function EmailList({
           }}
           onBatchUndoSpam={async () => {
             if (client) {
-              const emailIds = Array.from(selectedEmailIds);
+              const emailIds = Array.from(selectedEmailKeys);
               try {
                 await batchUndoSpam(client, emailIds);
                 const { toast } = await import('sonner');
diff --git a/components/email/thread-email-item.tsx b/components/email/thread-email-item.tsx
index 24c97d7e7..ca6b99aaf 100644
--- a/components/email/thread-email-item.tsx
+++ b/components/email/thread-email-item.tsx
@@ -45,9 +45,9 @@ export function ThreadEmailItem({
   // header pools them, so without this they disappear on the way in.
   const tagIds = sortTagIds(getEmailTagIds(email.keywords));
   const sender = email.from?.[0];
-  const { selectedMailbox, selectedEmailIds, toggleEmailSelection, selectRangeEmails, clearSelection } = useEmailStore();
+  const { selectedMailbox, selectedEmailKeys, toggleEmailSelection, selectRangeEmails, clearSelection } = useEmailStore();
   const density = useSettingsStore((state) => state.density);
-  const isChecked = selectedEmailIds.has(email.id);
+  const isChecked = selectedEmailKeys.has(email.id);
 
   const { dragHandlers, isDragging } = useEmailDrag({
     email,
@@ -73,18 +73,18 @@ export function ThreadEmailItem({
 
   const handleCheckboxClick = (e: React.MouseEvent) => {
     e.stopPropagation();
-    toggleEmailSelection(email.id);
+    toggleEmailSelection(email);
   };
 
   const handleClick = (e: React.MouseEvent) => {
     if (e.ctrlKey || e.metaKey) {
       e.preventDefault();
-      toggleEmailSelection(email.id);
+      toggleEmailSelection(email);
     } else if (e.shiftKey) {
       e.preventDefault();
-      selectRangeEmails(email.id);
+      selectRangeEmails(email);
     } else {
-      if (selectedEmailIds.size > 0) clearSelection();
+      if (selectedEmailKeys.size > 0) clearSelection();
       onClick?.();
     }
   };
@@ -118,7 +118,7 @@ export function ThreadEmailItem({
     >
       <div className="flex items-start gap-3">
         {/* Checkbox - only visible when in selection mode */}
-        {selectedEmailIds.size > 0 && (
+        {selectedEmailKeys.size > 0 && (
           <button
             onClick={handleCheckboxClick}
             className={cn(
diff --git a/components/email/thread-list-item.tsx b/components/email/thread-list-item.tsx
index 19ac9c4da..539d1b2a7 100644
--- a/components/email/thread-list-item.tsx
+++ b/components/email/thread-list-item.tsx
@@ -165,7 +165,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
     const isPinned = email.keywords?.['$pinned'] === true;
     const isAnswered = email.keywords?.$answered;
     const isForwarded = email.keywords?.$forwarded;
-    const { selectedMailbox, mailboxes, selectedEmailIds, toggleEmailSelection, selectRangeEmails, clearSelection, isUnifiedView, unifiedRole } = useEmailStore();
+    const { selectedMailbox, mailboxes, selectedEmailKeys, toggleEmailSelection, selectRangeEmails, clearSelection, isUnifiedView, unifiedRole } = useEmailStore();
     // In Sent/Drafts folders, show recipient instead of sender (which is always
     // "me"). In aggregate role-views the selected mailbox is virtual → fall back
     // to the unified role so junk-contextual UI and avatar hiding work.
@@ -187,7 +187,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
     const account = email.accountId ? getAccountById(email.accountId) : undefined;
     const accountColor = account?.avatarColor;
     const accountDescription = describeAccount(email.accountLabel, account);
-    const isChecked = selectedEmailIds.has(email.id);
+    const isChecked = selectedEmailKeys.has(email.id);
     const isMobile = useUIStore((state) => state.isMobile);
     // The horizontal one-line "focus" layout doesn't fit on narrow screens; fall back to multi-line on mobile.
     const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
@@ -267,9 +267,9 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
     const handleCheckboxClick = (e: React.MouseEvent) => {
       e.stopPropagation();
       if (e.shiftKey) {
-        selectRangeEmails(email.id);
+        selectRangeEmails(email);
       } else {
-        toggleEmailSelection(email.id);
+        toggleEmailSelection(email);
       }
     };
 
@@ -281,12 +281,12 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
       if (swipeEnabled && consumeTap()) { return; }
       if (e.ctrlKey || e.metaKey) {
         e.preventDefault();
-        toggleEmailSelection(email.id);
+        toggleEmailSelection(email);
       } else if (e.shiftKey) {
         e.preventDefault();
-        selectRangeEmails(email.id);
+        selectRangeEmails(email);
       } else {
-        if (selectedEmailIds.size > 0) clearSelection();
+        if (selectedEmailKeys.size > 0) clearSelection();
         onClick();
       }
     };
@@ -348,7 +348,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
           style={{ gap: 'var(--density-item-gap)', paddingBlock: 'var(--density-item-py)', transform: swipeEnabled && offsetX ? `translateX(${offsetX}px)` : undefined, transition: swipeEnabled && offsetX === 0 ? 'transform 200ms ease-out' : undefined }}
         >
           {/* Checkbox - only for extra-compact density (no avatar) while in selection mode */}
-          {density === 'extra-compact' && selectedEmailIds.size > 0 && (
+          {density === 'extra-compact' && selectedEmailKeys.size > 0 && (
             <button
               onClick={handleCheckboxClick}
               role="checkbox"
@@ -641,7 +641,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
       ? formatDateTime(latestEmail.scheduledSendAt, timeFormat)
       : null;
 
-    const { selectedMailbox, mailboxes, selectedEmailIds, toggleEmailSelection, selectRangeEmails, clearSelection, isUnifiedView, unifiedRole } = useEmailStore();
+    const { selectedMailbox, mailboxes, selectedEmailKeys, toggleEmailSelection, selectRangeEmails, clearSelection, isUnifiedView, unifiedRole } = useEmailStore();
     const showSourceFolder = isUnifiedView && !!latestEmail.sourceFolder;
     const getAccountById = useAccountStore((state) => state.getAccountById);
     const threadAccount = latestEmail.accountId ? getAccountById(latestEmail.accountId) : undefined;
@@ -688,7 +688,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
     const isSelected = selectedEmailId === latestEmail.id ||
       thread.emails.some(e => e.id === selectedEmailId);
 
-    const isChecked = thread.emails.some(e => selectedEmailIds.has(e.id));
+    const isChecked = thread.emails.some(e => selectedEmailKeys.has(e.id));
 
     if (emailCount === 1) {
       return (
@@ -717,8 +717,8 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
 
     // Toggle selection for all emails in this thread.
     const toggleThreadSelection = () => {
-      const allSelected = thread.emails.every(em => selectedEmailIds.has(em.id));
-      const newSelection = new Set(selectedEmailIds);
+      const allSelected = thread.emails.every(em => selectedEmailKeys.has(em.id));
+      const newSelection = new Set(selectedEmailKeys);
       thread.emails.forEach(em => {
         if (allSelected) {
           newSelection.delete(em.id);
@@ -726,13 +726,13 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
           newSelection.add(em.id);
         }
       });
-      useEmailStore.setState({ selectedEmailIds: newSelection, lastSelectedEmailId: latestEmail.id });
+      useEmailStore.setState({ selectedEmailKeys: newSelection, lastSelectedEmailKey: latestEmail.id });
     };
 
     const handleThreadCheckboxClick = (e: React.MouseEvent) => {
       e.stopPropagation();
       if (e.shiftKey) {
-        selectRangeEmails(latestEmail.id);
+        selectRangeEmails(latestEmail);
         return;
       }
       toggleThreadSelection();
@@ -742,12 +742,12 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
       if (e.ctrlKey || e.metaKey) {
         e.preventDefault();
         // Ctrl+Click: toggle selection for all thread emails
-        thread.emails.forEach(em => toggleEmailSelection(em.id));
+        thread.emails.forEach(em => toggleEmailSelection(em));
         return;
       }
       if (e.shiftKey) {
         e.preventDefault();
-        selectRangeEmails(latestEmail.id);
+        selectRangeEmails(latestEmail);
         return;
       }
 
@@ -760,7 +760,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
       if (target.closest('[data-expand-toggle]')) {
         onToggleExpand();
       } else {
-        if (selectedEmailIds.size > 0) clearSelection();
+        if (selectedEmailKeys.size > 0) clearSelection();
         if (!isExpanded) {
           onCollapseAllThreads?.();
           onToggleExpand();
@@ -812,7 +812,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
             style={{ gap: 'var(--density-item-gap)', paddingBlock: 'var(--density-item-py)' }}
           >
             {/* Checkbox for thread selection - only for extra-compact density (no avatar) while in selection mode */}
-            {density === 'extra-compact' && selectedEmailIds.size > 0 && (
+            {density === 'extra-compact' && selectedEmailKeys.size > 0 && (
               <button
                 onClick={handleThreadCheckboxClick}
                 role="checkbox"
diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index dc821d1d6..19c37a6d6 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -338,7 +338,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     newEmailNotification,
     selectEmail,
     selectMailbox,
-    selectedEmailIds,
+    selectedEmailKeys,
     selectAllEmails,
     clearSelection,
     toggleEmailSelection,
@@ -703,7 +703,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     },
     onArchive: async () => {
       if (isScheduledView) return;
-      if (selectedEmailIds.size > 0 && client) {
+      if (selectedEmailKeys.size > 0 && client) {
         try {
           await batchArchive(client);
         } catch (error) {
@@ -719,7 +719,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     },
     onDelete: async () => {
       if (isScheduledView) return;
-      if (selectedEmailIds.size > 0 && client) {
+      if (selectedEmailKeys.size > 0 && client) {
         const currentMailbox = mailboxes.find(m => m.id === selectedMailbox);
         const isInTrash = currentMailbox?.role === 'trash';
         const isInJunk = currentMailbox?.role === 'junk';
@@ -730,8 +730,8 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
             ? t('email_list.permanent_delete_confirm_title')
             : t('email_list.batch_actions.delete_confirm_title'),
           message: permanent
-            ? t('email_list.permanent_delete_confirm_batch_message', { count: selectedEmailIds.size })
-            : t('email_list.batch_actions.delete_confirm_message', { count: selectedEmailIds.size }),
+            ? t('email_list.permanent_delete_confirm_batch_message', { count: selectedEmailKeys.size })
+            : t('email_list.batch_actions.delete_confirm_message', { count: selectedEmailKeys.size }),
           confirmText: permanent
             ? t('email_list.permanent_delete')
             : t('email_list.batch_actions.delete'),
@@ -750,7 +750,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     onMarkAsUnread: async () => {
       if (isScheduledView) return;
       if (!client) return;
-      if (selectedEmailIds.size > 0) {
+      if (selectedEmailKeys.size > 0) {
         await batchMarkAsRead(client, false);
       } else if (selectedEmail) {
         await markAsRead(client, selectedEmail.id, false);
@@ -759,7 +759,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     onMarkAsRead: async () => {
       if (isScheduledView) return;
       if (!client) return;
-      if (selectedEmailIds.size > 0) {
+      if (selectedEmailKeys.size > 0) {
         await batchMarkAsRead(client, true);
       } else if (selectedEmail) {
         await markAsRead(client, selectedEmail.id, true);
@@ -773,8 +773,8 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       // is a no-op there too.
       if (['sent', 'drafts', 'scheduled'].includes(currentMailbox?.role || '')) return;
       const isInJunk = currentMailbox?.role === 'junk';
-      if (selectedEmailIds.size > 0 && client) {
-        const ids = Array.from(selectedEmailIds);
+      if (selectedEmailKeys.size > 0 && client) {
+        const ids = Array.from(selectedEmailKeys);
         try {
           if (isInJunk) {
             await batchUndoSpam(client, ids);
@@ -842,14 +842,14 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       }
     },
   // eslint-disable-next-line react-hooks/exhaustive-deps
-  }), [activeEmails, selectedEmail, client, selectedMailbox, isMobile, isTablet, selectedEmailIds, mailboxes, isScheduledView]);
+  }), [activeEmails, selectedEmail, client, selectedMailbox, isMobile, isTablet, selectedEmailKeys, mailboxes, isScheduledView]);
 
   // Initialize keyboard shortcuts
   useKeyboardShortcuts({
     enabled: isAuthenticated && !showComposer,
     emails: activeEmails,
     selectedEmailId: selectedEmail?.id,
-    selectionCount: selectedEmailIds.size,
+    selectionCount: selectedEmailKeys.size,
     handlers: keyboardHandlers,
   });
 
@@ -3706,30 +3706,32 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
                   <button
                     type="button"
                     onClick={() => {
-                      if (selectedEmailIds.size > 0) {
-                        if (selectedEmailIds.size === activeEmails.length) {
+                      if (selectedEmailKeys.size > 0) {
+                        if (selectedEmailKeys.size === activeEmails.length) {
                           clearSelection();
                         } else {
                           selectAllEmails();
                         }
                       } else if (activeEmails.length > 0) {
-                        const currentId = selectedEmail?.id;
-                        const target = currentId && activeEmails.some((e) => e.id === currentId)
-                          ? currentId
-                          : activeEmails[0].id;
+                        // The open message when it is in this list, else the
+                        // first row - as an email, so the selection is keyed by
+                        // its owning account and not by a colliding id.
+                        const target = (selectedEmail && activeEmails.some((e) => e.id === selectedEmail.id)
+                          ? activeEmails.find((e) => e.id === selectedEmail.id)
+                          : activeEmails[0])!;
                         toggleEmailSelection(target);
                       }
                     }}
                     disabled={isScheduledView}
                     className={cn(
                       "flex-shrink-0 p-2 rounded-md transition-colors",
-                      selectedEmailIds.size > 0
+                      selectedEmailKeys.size > 0
                         ? "bg-primary/10 text-primary"
                         : "text-muted-foreground hover:text-foreground hover:bg-muted"
                     )}
-                    title={isScheduledView ? t('email_viewer.scheduled_actions_only') : selectedEmailIds.size > 0 ? (selectedEmailIds.size === activeEmails.length ? t('email_list.batch_actions.clear_selection') : t('email_list.batch_actions.select_all')) : t('email_list.batch_actions.select')}
+                    title={isScheduledView ? t('email_viewer.scheduled_actions_only') : selectedEmailKeys.size > 0 ? (selectedEmailKeys.size === activeEmails.length ? t('email_list.batch_actions.clear_selection') : t('email_list.batch_actions.select_all')) : t('email_list.batch_actions.select')}
                   >
-                    {selectedEmailIds.size > 0 ? (
+                    {selectedEmailKeys.size > 0 ? (
                       <CheckSquare className="w-4 h-4" />
                     ) : (
                       <Square className="w-4 h-4" />
diff --git a/hooks/use-email-drag.ts b/hooks/use-email-drag.ts
index fb3a5f071..0bea4c299 100644
--- a/hooks/use-email-drag.ts
+++ b/hooks/use-email-drag.ts
@@ -141,7 +141,7 @@ function getReadyBundle(emails: Email[]): { url: string; name: string } | null {
 }
 
 export function useEmailDrag({ email, sourceMailboxId, threadEmails }: UseEmailDragOptions): UseEmailDragReturn {
-  const { selectedEmailIds, emails } = useEmailStore();
+  const { selectedEmailKeys, emails } = useEmailStore();
   const { startDrag, endDrag, isDragging, draggedEmails } = useDragDropContext();
   const isMobile = useUIStore((state) => state.isMobile);
   const client = useAuthStore((state) => state.client);
@@ -195,10 +195,10 @@ export function useEmailDrag({ email, sourceMailboxId, threadEmails }: UseEmailD
 
   const handlePointerEnter = useCallback(() => {
     if (!dragOutEnabled || !client) return;
-    const isSelected = selectedEmailIds.has(email.id);
-    const isMulti = isSelected && selectedEmailIds.size > 1;
+    const isSelected = selectedEmailKeys.has(email.id);
+    const isMulti = isSelected && selectedEmailKeys.size > 1;
     if (isMulti) {
-      const selected = emails.filter((em) => selectedEmailIds.has(em.id));
+      const selected = emails.filter((em) => selectedEmailKeys.has(em.id));
       // Only worth bundling when at least one selected email has a blobId.
       if (selected.some((em) => em.blobId)) {
         prefetchEmailBundle(client, selected, filenameOptions, bundleOptions);
@@ -206,16 +206,16 @@ export function useEmailDrag({ email, sourceMailboxId, threadEmails }: UseEmailD
     } else {
       prefetchSingle();
     }
-  }, [dragOutEnabled, client, selectedEmailIds, email.id, emails, prefetchSingle, filenameOptions, bundleOptions]);
+  }, [dragOutEnabled, client, selectedEmailKeys, email.id, emails, prefetchSingle, filenameOptions, bundleOptions]);
 
   const handleDragStart = useCallback((e: DragEvent<HTMLDivElement>) => {
     // Determine which emails to drag:
     // - If current email is selected, drag all selected
     // - If threadEmails provided (thread header), drag all thread emails
     // - Otherwise, drag only this email
-    const isSelected = selectedEmailIds.has(email.id);
+    const isSelected = selectedEmailKeys.has(email.id);
     const emailsToDrag = isSelected
-      ? emails.filter(em => selectedEmailIds.has(em.id))
+      ? emails.filter(em => selectedEmailKeys.has(em.id))
       : threadEmails || [email];
 
     e.dataTransfer.effectAllowed = "copyMove";
@@ -284,7 +284,7 @@ export function useEmailDrag({ email, sourceMailboxId, threadEmails }: UseEmailD
     });
 
     startDrag(emailsToDrag, sourceMailboxId);
-  }, [email, selectedEmailIds, emails, sourceMailboxId, startDrag, threadEmails, dragOutEnabled, client, prefetchSingle, filenameOptions, bundleOptions]);
+  }, [email, selectedEmailKeys, emails, sourceMailboxId, startDrag, threadEmails, dragOutEnabled, client, prefetchSingle, filenameOptions, bundleOptions]);
 
   const handleDragEnd = useCallback(() => {
     endDrag();
diff --git a/hooks/use-mailbox-drop.ts b/hooks/use-mailbox-drop.ts
index 4954423ca..2b87b6665 100644
--- a/hooks/use-mailbox-drop.ts
+++ b/hooks/use-mailbox-drop.ts
@@ -65,7 +65,7 @@ interface UseMailboxDropReturn {
 export function useMailboxDrop({ mailbox, onDropComplete, onSuccess, onError }: UseMailboxDropOptions): UseMailboxDropReturn {
   const [isOver, setIsOver] = useState(false);
   const { client } = useAuthStore();
-  const { moveEmailsToMailbox, crossAccountMoveEmails, selectedEmailIds, clearSelection, refreshCurrentMailbox, mailboxes } = useEmailStore();
+  const { moveEmailsToMailbox, crossAccountMoveEmails, selectedEmailKeys, clearSelection, refreshCurrentMailbox, mailboxes } = useEmailStore();
   const { isDragging, sourceMailboxId, draggedEmails, endDrag } = useDragDropContext();
 
   // Determine if this is a valid drop target
@@ -184,7 +184,7 @@ export function useMailboxDrop({ mailbox, onDropComplete, onSuccess, onError }:
       }
 
       // Clear selection if any selected emails were moved
-      if (emailIds.some(id => selectedEmailIds.has(id))) {
+      if (emailIds.some(id => selectedEmailKeys.has(id))) {
         clearSelection();
       }
 
@@ -222,7 +222,7 @@ export function useMailboxDrop({ mailbox, onDropComplete, onSuccess, onError }:
     } finally {
       endDrag();
     }
-  }, [client, mailbox, mailboxes, isValidTarget, moveEmailsToMailbox, crossAccountMoveEmails, draggedEmails, sourceMailboxId, selectedEmailIds, clearSelection, refreshCurrentMailbox, endDrag, onDropComplete, onSuccess, onError]);
+  }, [client, mailbox, mailboxes, isValidTarget, moveEmailsToMailbox, crossAccountMoveEmails, draggedEmails, sourceMailboxId, selectedEmailKeys, clearSelection, refreshCurrentMailbox, endDrag, onDropComplete, onSuccess, onError]);
 
   const valid = isValidTarget();
 
diff --git a/lib/__tests__/account-state-manager.test.ts b/lib/__tests__/account-state-manager.test.ts
index 3ad649036..3231a34e8 100644
--- a/lib/__tests__/account-state-manager.test.ts
+++ b/lib/__tests__/account-state-manager.test.ts
@@ -94,7 +94,7 @@ describe('clearAllStores', () => {
   it('resets the email store to fresh empty collections', () => {
     useEmailStore.setState({
       emails: [makeEmail({ id: 'x' })],
-      selectedEmailIds: new Set(['x']),
+      selectedEmailKeys: new Set(['x']),
       searchQuery: 'q',
       tagCounts: { a: { total: 1, unread: 0 } },
       threadEmailsCache: new Map([['t', []]]),
@@ -105,7 +105,7 @@ describe('clearAllStores', () => {
     const s = useEmailStore.getState();
     expect(s.emails).toEqual([]);
     expect(s.searchQuery).toBe('');
-    expect(s.selectedEmailIds.size).toBe(0);
+    expect(s.selectedEmailKeys.size).toBe(0);
     expect(s.threadEmailsCache.size).toBe(0);
     expect(s.tagCounts).toEqual({});
     expect(s.searchFilters).toEqual(DEFAULT_SEARCH_FILTERS);
diff --git a/lib/account-state-manager.ts b/lib/account-state-manager.ts
index 92fdb092d..d0753a303 100644
--- a/lib/account-state-manager.ts
+++ b/lib/account-state-manager.ts
@@ -117,7 +117,7 @@ export function clearAllStores(): void {
     isPushConnected: false,
     lastPushUpdate: null,
     newEmailNotification: null,
-    selectedEmailIds: new Set<string>(),
+    selectedEmailKeys: new Set<string>(),
     hasMoreEmails: false,
     totalEmails: 0,
     expandedThreadIds: new Set<string>(),
diff --git a/lib/thread-utils.ts b/lib/thread-utils.ts
index a3476c6ec..991da6eb5 100644
--- a/lib/thread-utils.ts
+++ b/lib/thread-utils.ts
@@ -19,6 +19,23 @@ export function threadKeyFor(
   return scope ? `${scope}:${email.threadId}` : email.threadId;
 }
 
+/**
+ * Client-side identity of a single message.
+ *
+ * Email ids are per-account too, so in a merged view two unrelated messages can
+ * share an `id` - `eiaaaabc` exists in every account that got that far. Batch
+ * selection is what makes that dangerous: keyed by the bare id, ticking one row
+ * also ticks its namesake in another account, and delete, move or archive then
+ * act on both. Same scoping as `threadKeyFor`; unstamped emails keep the bare
+ * id, so single-account views are untouched.
+ */
+export function emailKeyFor(
+  email: Pick<Email, "id" | "sourceClientAccountId" | "sourceAccountId">,
+): string {
+  const scope = [email.sourceClientAccountId, email.sourceAccountId].filter(Boolean).join("/");
+  return scope ? `${scope}:${email.id}` : email.id;
+}
+
 /**
  * The JMAP thread id behind a `threadKeyFor` key. JMAP ids never contain ":"
  * (RFC 8620 §1.2 limits them to the URL-safe base64 alphabet), so the last
diff --git a/stores/__tests__/email-archive.test.ts b/stores/__tests__/email-archive.test.ts
index 2522b58a0..c8b3ef67f 100644
--- a/stores/__tests__/email-archive.test.ts
+++ b/stores/__tests__/email-archive.test.ts
@@ -61,7 +61,7 @@ describe('email-store archive thread behavior', () => {
       mailboxes: [inbox, archive],
       selectedMailbox: 'shared-inbox',
       selectedEmail: threadEmailA,
-      selectedEmailIds: new Set(['email-1', 'email-2']),
+      selectedEmailKeys: new Set(['email-1', 'email-2']),
       expandedThreadIds: new Set(['thread-1']),
       threadEmailsCache: new Map([['thread-1', [threadEmailA, threadEmailB]]]),
       error: null,
@@ -82,7 +82,7 @@ describe('email-store archive thread behavior', () => {
     const state = useEmailStore.getState();
     expect(state.emails.map(email => email.id)).toEqual(['email-3']);
     expect(state.selectedEmail?.id).toBe('email-3');
-    expect(Array.from(state.selectedEmailIds)).toEqual([]);
+    expect(Array.from(state.selectedEmailKeys)).toEqual([]);
     expect(state.expandedThreadIds.has('thread-1')).toBe(false);
     expect(state.threadEmailsCache.has('thread-1')).toBe(false);
   });
diff --git a/stores/__tests__/email-selection-cross-account.test.ts b/stores/__tests__/email-selection-cross-account.test.ts
new file mode 100644
index 000000000..cedb7a64f
--- /dev/null
+++ b/stores/__tests__/email-selection-cross-account.test.ts
@@ -0,0 +1,62 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { useEmailStore } from '../email-store';
+import { emailKeyFor } from '@/lib/thread-utils';
+import type { Email } from '@/lib/jmap/types';
+
+/**
+ * Email ids are per-account, so the same id exists in several accounts
+ * ("eiaaaabc" is an ordinary first id). Reported on #1013 by @alyyousuf7:
+ * selection keyed by the bare id ticks both, and a batch action then hits a
+ * message the user never selected.
+ */
+const twin = (account: string, subject: string): Email => ({
+  id: 'eiaaaabc', threadId: 'taaaabc', blobId: `blob-${account}`,
+  mailboxIds: { inbox: true }, keywords: {},
+  from: [{ email: `someone@${account}` }], to: [], subject,
+  receivedAt: '2026-09-19T08:00:00Z', size: 42, preview: '', hasAttachment: false,
+  sourceClientAccountId: account, sourceAccountId: account,
+} as unknown as Email);
+
+const mine = twin('account-a', 'mia');
+const theirs = twin('account-b', 'di un altro account');
+
+beforeEach(() => {
+  useEmailStore.setState({ emails: [mine, theirs], selectedEmailKeys: new Set(), lastSelectedEmailKey: null });
+});
+
+describe('selection across accounts sharing an email id', () => {
+  it('ticks only the row that was clicked', () => {
+    useEmailStore.getState().toggleEmailSelection(mine);
+    const { emails, selectedEmailKeys } = useEmailStore.getState();
+    const affected = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
+    expect(affected).toHaveLength(1);
+    expect(affected[0]!.sourceAccountId).toBe('account-a');
+  });
+
+  it('unticks its namesake independently', () => {
+    const store = useEmailStore.getState();
+    store.toggleEmailSelection(mine);
+    store.toggleEmailSelection(theirs);
+    expect(useEmailStore.getState().selectedEmailKeys.size).toBe(2);
+    store.toggleEmailSelection(theirs);
+    const { selectedEmailKeys } = useEmailStore.getState();
+    expect([...selectedEmailKeys]).toEqual([emailKeyFor(mine)]);
+  });
+
+  it('selects every account copy when the whole list is selected', () => {
+    useEmailStore.getState().selectAllEmails();
+    expect(useEmailStore.getState().selectedEmailKeys.size).toBe(2);
+  });
+
+  it('deletes only the selected account copy', async () => {
+    const client = {
+      batchDeleteEmails: vi.fn(async () => {}),
+      batchMoveToMailbox: vi.fn(async () => {}),
+      getMailboxes: vi.fn(async () => []),
+    } as never;
+    useEmailStore.getState().toggleEmailSelection(theirs);
+    await useEmailStore.getState().batchDelete(client, true);
+    const remaining = useEmailStore.getState().emails;
+    expect(remaining.map(e => e.sourceAccountId)).toEqual(['account-a']);
+  });
+});
diff --git a/stores/__tests__/email-selection.test.ts b/stores/__tests__/email-selection.test.ts
index 6c7411d91..51dffe4d0 100644
--- a/stores/__tests__/email-selection.test.ts
+++ b/stores/__tests__/email-selection.test.ts
@@ -24,29 +24,29 @@ describe('email-store selection', () => {
   beforeEach(() => {
     useEmailStore.setState({
       emails: [makeEmail('a'), makeEmail('b'), makeEmail('c'), makeEmail('d'), makeEmail('e')],
-      selectedEmailIds: new Set(),
-      lastSelectedEmailId: null,
+      selectedEmailKeys: new Set(),
+      lastSelectedEmailKey: null,
       selectedEmail: null,
     });
   });
 
   describe('toggleEmailSelection', () => {
     it('should add email to selection', () => {
-      useEmailStore.getState().toggleEmailSelection('b');
-      expect(useEmailStore.getState().selectedEmailIds.has('b')).toBe(true);
-      expect(useEmailStore.getState().lastSelectedEmailId).toBe('b');
+      useEmailStore.getState().toggleEmailSelection({ id: 'b' });
+      expect(useEmailStore.getState().selectedEmailKeys.has('b')).toBe(true);
+      expect(useEmailStore.getState().lastSelectedEmailKey).toBe('b');
     });
 
     it('should remove email from selection when toggled again', () => {
-      useEmailStore.getState().toggleEmailSelection('b');
-      useEmailStore.getState().toggleEmailSelection('b');
-      expect(useEmailStore.getState().selectedEmailIds.has('b')).toBe(false);
+      useEmailStore.getState().toggleEmailSelection({ id: 'b' });
+      useEmailStore.getState().toggleEmailSelection({ id: 'b' });
+      expect(useEmailStore.getState().selectedEmailKeys.has('b')).toBe(false);
     });
 
     it('should support selecting multiple emails', () => {
-      useEmailStore.getState().toggleEmailSelection('a');
-      useEmailStore.getState().toggleEmailSelection('c');
-      const ids = useEmailStore.getState().selectedEmailIds;
+      useEmailStore.getState().toggleEmailSelection({ id: 'a' });
+      useEmailStore.getState().toggleEmailSelection({ id: 'c' });
+      const ids = useEmailStore.getState().selectedEmailKeys;
       expect(ids.has('a')).toBe(true);
       expect(ids.has('c')).toBe(true);
       expect(ids.size).toBe(2);
@@ -55,9 +55,9 @@ describe('email-store selection', () => {
 
   describe('selectRangeEmails', () => {
     it('should select range from last selected to target (forward)', () => {
-      useEmailStore.getState().toggleEmailSelection('b'); // anchor at index 1
-      useEmailStore.getState().selectRangeEmails('d'); // target at index 3
-      const ids = useEmailStore.getState().selectedEmailIds;
+      useEmailStore.getState().toggleEmailSelection({ id: 'b' }); // anchor at index 1
+      useEmailStore.getState().selectRangeEmails({ id: 'd' }); // target at index 3
+      const ids = useEmailStore.getState().selectedEmailKeys;
       expect(ids.has('b')).toBe(true);
       expect(ids.has('c')).toBe(true);
       expect(ids.has('d')).toBe(true);
@@ -65,9 +65,9 @@ describe('email-store selection', () => {
     });
 
     it('should select range backward', () => {
-      useEmailStore.getState().toggleEmailSelection('d'); // anchor at index 3
-      useEmailStore.getState().selectRangeEmails('b'); // target at index 1
-      const ids = useEmailStore.getState().selectedEmailIds;
+      useEmailStore.getState().toggleEmailSelection({ id: 'd' }); // anchor at index 3
+      useEmailStore.getState().selectRangeEmails({ id: 'b' }); // target at index 1
+      const ids = useEmailStore.getState().selectedEmailKeys;
       expect(ids.has('b')).toBe(true);
       expect(ids.has('c')).toBe(true);
       expect(ids.has('d')).toBe(true);
@@ -75,8 +75,8 @@ describe('email-store selection', () => {
     });
 
     it('should use first email as anchor when no previous selection', () => {
-      useEmailStore.getState().selectRangeEmails('c'); // no anchor → uses first email 'a'
-      const ids = useEmailStore.getState().selectedEmailIds;
+      useEmailStore.getState().selectRangeEmails({ id: 'c' }); // no anchor → uses first email 'a'
+      const ids = useEmailStore.getState().selectedEmailKeys;
       expect(ids.has('a')).toBe(true);
       expect(ids.has('b')).toBe(true);
       expect(ids.has('c')).toBe(true);
@@ -84,10 +84,10 @@ describe('email-store selection', () => {
     });
 
     it('should add to existing selection', () => {
-      useEmailStore.getState().toggleEmailSelection('a');
-      useEmailStore.getState().toggleEmailSelection('b'); // anchor now at 'b'
-      useEmailStore.getState().selectRangeEmails('d');
-      const ids = useEmailStore.getState().selectedEmailIds;
+      useEmailStore.getState().toggleEmailSelection({ id: 'a' });
+      useEmailStore.getState().toggleEmailSelection({ id: 'b' }); // anchor now at 'b'
+      useEmailStore.getState().selectRangeEmails({ id: 'd' });
+      const ids = useEmailStore.getState().selectedEmailKeys;
       // 'a' still selected, plus b-d range
       expect(ids.has('a')).toBe(true);
       expect(ids.has('b')).toBe(true);
@@ -97,9 +97,9 @@ describe('email-store selection', () => {
     });
 
     it('should handle single-item range', () => {
-      useEmailStore.getState().toggleEmailSelection('c');
-      useEmailStore.getState().selectRangeEmails('c');
-      const ids = useEmailStore.getState().selectedEmailIds;
+      useEmailStore.getState().toggleEmailSelection({ id: 'c' });
+      useEmailStore.getState().selectRangeEmails({ id: 'c' });
+      const ids = useEmailStore.getState().selectedEmailKeys;
       expect(ids.has('c')).toBe(true);
       expect(ids.size).toBe(1);
     });
@@ -108,17 +108,17 @@ describe('email-store selection', () => {
   describe('selectAllEmails', () => {
     it('should select all emails', () => {
       useEmailStore.getState().selectAllEmails();
-      expect(useEmailStore.getState().selectedEmailIds.size).toBe(5);
+      expect(useEmailStore.getState().selectedEmailKeys.size).toBe(5);
     });
   });
 
   describe('clearSelection', () => {
     it('should clear all selections and reset anchor', () => {
-      useEmailStore.getState().toggleEmailSelection('a');
-      useEmailStore.getState().toggleEmailSelection('b');
+      useEmailStore.getState().toggleEmailSelection({ id: 'a' });
+      useEmailStore.getState().toggleEmailSelection({ id: 'b' });
       useEmailStore.getState().clearSelection();
-      expect(useEmailStore.getState().selectedEmailIds.size).toBe(0);
-      expect(useEmailStore.getState().lastSelectedEmailId).toBeNull();
+      expect(useEmailStore.getState().selectedEmailKeys.size).toBe(0);
+      expect(useEmailStore.getState().lastSelectedEmailKey).toBeNull();
     });
   });
 });
diff --git a/stores/__tests__/email-store-archive-missing.test.ts b/stores/__tests__/email-store-archive-missing.test.ts
index cce2d45f5..983cff55b 100644
--- a/stores/__tests__/email-store-archive-missing.test.ts
+++ b/stores/__tests__/email-store-archive-missing.test.ts
@@ -74,7 +74,7 @@ describe('batchArchive without an archive mailbox (#578)', () => {
       ],
       accountMailboxes: {},
       emails: [makeEmail({ id: 'e1', mailboxIds: { 'a-inbox': true } })],
-      selectedEmailIds: new Set(['e1']),
+      selectedEmailKeys: new Set(['e1']),
     });
   });
 
@@ -86,6 +86,6 @@ describe('batchArchive without an archive mailbox (#578)', () => {
     expect(useEmailStore.getState().error).toMatch(/archive mailbox not found/i);
     expect(client.batchArchiveEmails).not.toHaveBeenCalled();
     // Nothing was archived, so the selection must survive.
-    expect(useEmailStore.getState().selectedEmailIds.has('e1')).toBe(true);
+    expect(useEmailStore.getState().selectedEmailKeys.has('e1')).toBe(true);
   });
 });
diff --git a/stores/__tests__/email-store-multi-account.test.ts b/stores/__tests__/email-store-multi-account.test.ts
index 02a5cacbb..280be7514 100644
--- a/stores/__tests__/email-store-multi-account.test.ts
+++ b/stores/__tests__/email-store-multi-account.test.ts
@@ -36,7 +36,7 @@ describe('useEmailStore multi-account state', () => {
       viewingAccountId: null,
       selectedMailbox: '',
       selectedEmail: null,
-      selectedEmailIds: new Set(),
+      selectedEmailKeys: new Set(),
       selectedKeyword: null,
       expandedThreadIds: new Set(),
       threadEmailsCache: new Map(),
@@ -89,7 +89,7 @@ describe('useEmailStore multi-account state', () => {
   it('selectAccountMailbox sets viewing and selected together, and clears email selection state', () => {
     useEmailStore.setState({
       selectedEmail: { id: 'e1' } as unknown as ReturnType<typeof useEmailStore.getState>['selectedEmail'],
-      selectedEmailIds: new Set(['e1', 'e2']),
+      selectedEmailKeys: new Set(['e1', 'e2']),
       selectedKeyword: 'work',
       expandedThreadIds: new Set(['thread-1']),
     });
@@ -100,7 +100,7 @@ describe('useEmailStore multi-account state', () => {
     expect(state.viewingAccountId).toBe('account-b');
     expect(state.selectedMailbox).toBe('b-inbox');
     expect(state.selectedEmail).toBeNull();
-    expect(state.selectedEmailIds.size).toBe(0);
+    expect(state.selectedEmailKeys.size).toBe(0);
     expect(state.selectedKeyword).toBeNull();
     expect(state.expandedThreadIds.size).toBe(0);
   });
diff --git a/stores/__tests__/email-store-retained-in-view.test.ts b/stores/__tests__/email-store-retained-in-view.test.ts
index 43e2df61f..cdf3f1ba7 100644
--- a/stores/__tests__/email-store-retained-in-view.test.ts
+++ b/stores/__tests__/email-store-retained-in-view.test.ts
@@ -78,7 +78,7 @@ function seedView(id: typeof CROSS_UNREAD | typeof CROSS_STARRED, view: 'unread'
     mailboxes: [makeMailbox()],
     accountMailboxes: { 'account-a': [makeMailbox()] },
     processingReadStatus: new Set(),
-    selectedEmailIds: new Set(),
+    selectedEmailKeys: new Set(),
     retainedInViewIds: new Set(),
     emails,
     totalEmails: emails.length,
@@ -194,7 +194,7 @@ describe('retained-in-view: scope', () => {
       isUnifiedView: true, unifiedRole: null, crossView: 'all', selectedMailbox: '__cross_all__',
       selectedKeyword: null, searchQuery: '', mailboxes: [makeMailbox()],
       accountMailboxes: { 'account-a': [makeMailbox()] },
-      processingReadStatus: new Set(), selectedEmailIds: new Set(), retainedInViewIds: new Set(),
+      processingReadStatus: new Set(), selectedEmailKeys: new Set(), retainedInViewIds: new Set(),
       emails: [a], totalEmails: 1,
     });
 
diff --git a/stores/__tests__/email-store-shared-folder-actions.test.ts b/stores/__tests__/email-store-shared-folder-actions.test.ts
index e778c807c..dd3e55830 100644
--- a/stores/__tests__/email-store-shared-folder-actions.test.ts
+++ b/stores/__tests__/email-store-shared-folder-actions.test.ts
@@ -118,7 +118,7 @@ describe('non-unified shared-folder batch action routing', () => {
         makeEmail({ id: 'e1', keywords: {}, mailboxIds: { 'owner-x:x-inbox': true } }),
         makeEmail({ id: 'e2', keywords: {}, mailboxIds: { 'owner-x:x-inbox': true } }),
       ],
-      selectedEmailIds: new Set(['e1', 'e2']),
+      selectedEmailKeys: new Set(['e1', 'e2']),
     });
   });
 
@@ -185,7 +185,7 @@ describe('non-unified shared-folder batch action routing', () => {
         makeEmail({ id: 'o1', keywords: {}, mailboxIds: { 'a-inbox': true } }),
         makeEmail({ id: 'o2', keywords: {}, mailboxIds: { 'a-inbox': true } }),
       ],
-      selectedEmailIds: new Set(['o1', 'o2']),
+      selectedEmailKeys: new Set(['o1', 'o2']),
     });
 
     await useEmailStore.getState().batchDelete(activeClient, false);
diff --git a/stores/__tests__/email-store-shared-folder-keywords.test.ts b/stores/__tests__/email-store-shared-folder-keywords.test.ts
index 97659d646..ff51348aa 100644
--- a/stores/__tests__/email-store-shared-folder-keywords.test.ts
+++ b/stores/__tests__/email-store-shared-folder-keywords.test.ts
@@ -101,7 +101,7 @@ describe('non-unified shared-folder keyword routing', () => {
       accountMailboxes: {},
       selectedEmail: null,
       emails: [makeEmail({ id: 'e1', keywords: {}, mailboxIds: { 'owner-x:x-inbox': true } })],
-      selectedEmailIds: new Set<string>(),
+      selectedEmailKeys: new Set<string>(),
     } as never);
   });
 
diff --git a/stores/__tests__/email-store-tag-counts.test.ts b/stores/__tests__/email-store-tag-counts.test.ts
index b99ea9fdf..fd3cd50ea 100644
--- a/stores/__tests__/email-store-tag-counts.test.ts
+++ b/stores/__tests__/email-store-tag-counts.test.ts
@@ -86,7 +86,7 @@ describe('email-store tag counts stay in step with read state', () => {
       accountMailboxes: {},
       emails: [],
       selectedEmail: null,
-      selectedEmailIds: new Set(),
+      selectedEmailKeys: new Set(),
       processingReadStatus: new Set(),
       threadEmailsCache: new Map(),
       tagCounts: {
@@ -187,7 +187,7 @@ describe('email-store tag counts stay in step with read state', () => {
           // Untagged: must not contribute a delta.
           makeEmail({ id: 'e4', keywords: {} }),
         ],
-        selectedEmailIds: new Set(['e1', 'e2', 'e3', 'e4']),
+        selectedEmailKeys: new Set(['e1', 'e2', 'e3', 'e4']),
       } as never);
 
       await useEmailStore.getState().batchMarkAsRead(client, true);
diff --git a/stores/__tests__/email-store-tag-view-accounts.test.ts b/stores/__tests__/email-store-tag-view-accounts.test.ts
index c1a896315..c4fed1fdf 100644
--- a/stores/__tests__/email-store-tag-view-accounts.test.ts
+++ b/stores/__tests__/email-store-tag-view-accounts.test.ts
@@ -1,5 +1,6 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { useEmailStore } from '../email-store';
+import { emailKeyFor } from '@/lib/thread-utils';
 import { useSettingsStore } from '../settings-store';
 import { useAuthStore } from '../auth-store';
 import { useMessageListTabsStore } from '../message-list-tabs-store';
@@ -137,7 +138,10 @@ describe('tag view across the own and group accounts (#1038)', () => {
     useEmailStore.setState({ selectedMailbox: groupInbox.id });
     useEmailStore.getState().selectKeyword(label);
     await useEmailStore.getState().fetchEmails(client);
-    useEmailStore.setState({ selectedEmailIds: new Set(['own-1', 'grp-1']) });
+    // Keyed by owning account: in this very view 'own-1' and 'grp-1' could be
+    // the same bare id in two accounts.
+    const picked = useEmailStore.getState().emails.filter(e => ['own-1', 'grp-1'].includes(e.id));
+    useEmailStore.setState({ selectedEmailKeys: new Set(picked.map(emailKeyFor)) });
 
     await useEmailStore.getState().batchMarkAsRead(client, true);
 
diff --git a/stores/__tests__/email-store-unified-actions.test.ts b/stores/__tests__/email-store-unified-actions.test.ts
index 68a782b8f..fb50d14fe 100644
--- a/stores/__tests__/email-store-unified-actions.test.ts
+++ b/stores/__tests__/email-store-unified-actions.test.ts
@@ -1,5 +1,6 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { useEmailStore } from '../email-store';
+import { emailKeyFor } from '@/lib/thread-utils';
 import { useAuthStore } from '../auth-store';
 import type { Email, Mailbox } from '@/lib/jmap/types';
 import type { IJMAPClient } from '@/lib/jmap/client-interface';
@@ -98,7 +99,7 @@ describe('unified-view single-email action routing (#281)', () => {
       },
       processingReadStatus: new Set(),
       selectedEmail: null,
-      selectedEmailIds: new Set(),
+      selectedEmailKeys: new Set(),
       unifiedScope: [],
       unifiedCounts: [],
       crossUnreadCount: 0,
@@ -164,7 +165,10 @@ describe('unified-view single-email action routing (#281)', () => {
         makeEmail({ id: 'a1', sourceClientAccountId: 'account-a', sourceAccountId: 'account-a', keywords: {}, mailboxIds: { inbox: true } }),
         makeEmail({ id: 'b1', sourceClientAccountId: 'account-b', sourceAccountId: 'account-b', keywords: {}, mailboxIds: { inbox: true } }),
       ],
-      selectedEmailIds: new Set(['a1', 'b1']),
+      selectedEmailKeys: new Set([
+        emailKeyFor({ id: 'a1', sourceClientAccountId: 'account-a', sourceAccountId: 'account-a' }),
+        emailKeyFor({ id: 'b1', sourceClientAccountId: 'account-b', sourceAccountId: 'account-b' }),
+      ]),
     });
 
     await useEmailStore.getState().batchMarkAsRead(activeClient, true);
@@ -209,7 +213,9 @@ describe('unified-view single-email action routing (#281)', () => {
           mailboxIds: { 'x-inbox': true }, // BARE owner id (not namespaced)
         }),
       ],
-      selectedEmailIds: new Set(['email-shared']),
+      selectedEmailKeys: new Set([
+        emailKeyFor({ id: 'email-shared', sourceClientAccountId: 'account-a', sourceAccountId: 'owner-x' }),
+      ]),
     });
 
     await useEmailStore.getState().batchDelete(activeClient, true);
@@ -255,7 +261,9 @@ describe('unified-view single-email action routing (#281)', () => {
           mailboxIds: { 'x-inbox': true }, // BARE owner id (not namespaced)
         }),
       ],
-      selectedEmailIds: new Set(['email-shared']),
+      selectedEmailKeys: new Set([
+        emailKeyFor({ id: 'email-shared', sourceClientAccountId: 'account-a', sourceAccountId: 'owner-x' }),
+      ]),
     });
 
     // Seed the badges from the scope (also stores unifiedScope).
diff --git a/stores/email-store.ts b/stores/email-store.ts
index c10ac3a1a..33d25acf5 100644
--- a/stores/email-store.ts
+++ b/stores/email-store.ts
@@ -8,7 +8,7 @@ import type { SortLevel } from "@/lib/message-list-order";
 import { SearchFilters, DEFAULT_SEARCH_FILTERS, buildJMAPFilter, isFilterEmpty } from "@/lib/jmap/search-utils";
 import { emailHooks } from "@/lib/plugin-hooks";
 import { resolveThreadRoute } from "@/lib/thread-routing";
-import { threadKeyFor, threadIdFromKey } from "@/lib/thread-utils";
+import { emailKeyFor, threadKeyFor, threadIdFromKey } from "@/lib/thread-utils";
 import type { ExternalSearchResult } from "@/lib/plugin-types";
 import { fetchUnifiedEmails, fetchUnifiedMailboxCounts, searchUnifiedEmails, advancedSearchUnifiedEmails, fetchCrossViewEmails, searchCrossViewEmails, advancedSearchCrossViewEmails, fetchTagEmails, getCrossUnreadTotal, type UnifiedAccountClient, type UnifiedMailboxCounts } from "@/lib/unified-mailbox";
 import { useAuthStore } from "@/stores/auth-store";
@@ -41,6 +41,19 @@ type PendingUndoSend = {
   submissionAccountId?: string;
 };
 
+/** Drop the matching emails from a key-based selection. */
+function dropFromSelection(
+  state: { emails: Email[]; selectedEmailKeys: Set<string> },
+  matches: (email: Email) => boolean,
+): Set<string> {
+  const next = new Set(state.selectedEmailKeys);
+  for (const email of state.emails) if (matches(email)) next.delete(emailKeyFor(email));
+  return next;
+}
+
+/** Enough of an email to key a selection by its owning account. */
+type SelectableEmail = Pick<Email, 'id' | 'sourceClientAccountId' | 'sourceAccountId'>;
+
 interface EmailStore {
   emails: Email[];
   mailboxes: Mailbox[];
@@ -68,7 +81,7 @@ interface EmailStore {
   searchQuery: string;
   quota: { used: number; total: number } | null;
   processingReadStatus: Set<string>; // Track emails being marked as read/unread
-  selectedEmailIds: Set<string>; // Track selected emails for batch operations
+  selectedEmailKeys: Set<string>; // Track selected emails for batch operations
   // Emails the user just read (unread view) or unstarred (starred view) that
   // should stay visible in that self-filtering cross view until it is re-opened,
   // instead of vanishing on the next push refresh. Cleared on navigation.
@@ -189,9 +202,10 @@ interface EmailStore {
   setQuota: (quota: { used: number; total: number } | null) => void;
   selectKeyword: (keyword: string | null) => void;
   fetchTagCounts: (client: IJMAPClient) => Promise<void>;
-  toggleEmailSelection: (emailId: string) => void;
-  selectRangeEmails: (targetEmailId: string) => void;
-  lastSelectedEmailId: string | null;
+  /** Take the email, not its id: the id alone collides across accounts. */
+  toggleEmailSelection: (email: SelectableEmail) => void;
+  selectRangeEmails: (target: SelectableEmail) => void;
+  lastSelectedEmailKey: string | null;
   selectAllEmails: () => void;
   clearSelection: () => void;
 
@@ -1356,9 +1370,9 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   searchQuery: "",
   quota: null,
   processingReadStatus: new Set(),
-  selectedEmailIds: new Set(),
+  selectedEmailKeys: new Set(),
   retainedInViewIds: new Set(),
-  lastSelectedEmailId: null,
+  lastSelectedEmailKey: null,
   hasMoreEmails: false,
   totalEmails: 0,
   listOrder: [],
@@ -1422,7 +1436,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     selectedMailbox: mailboxId,
     isLoadingMore: false,
     selectedEmail: null,
-    selectedEmailIds: new Set(),
+    selectedEmailKeys: new Set(),
     selectedKeyword: null,
     expandedThreadIds: new Set(),
     threadEmailsCache: new Map(),
@@ -1455,7 +1469,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   },
   selectEmail: (email) => {
     const prev = get().selectedEmail;
-    set({ selectedEmail: email, lastSelectedEmailId: email?.id ?? get().lastSelectedEmailId });
+    set({ selectedEmail: email, lastSelectedEmailKey: email?.id ?? get().lastSelectedEmailKey });
     if (prev && (!email || email.id !== prev.id)) {
       emailHooks.onEmailClose.emitSync(prev);
     }
@@ -1467,7 +1481,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     selectedKeyword: keyword,
     isLoadingMore: false,
     selectedEmail: null,
-    selectedEmailIds: new Set(),
+    selectedEmailKeys: new Set(),
     expandedThreadIds: new Set(),
     threadEmailsCache: new Map(),
     threadEmailCounts: new Map(),
@@ -1504,7 +1518,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     selectedMailbox: mailboxId,
     isLoadingMore: false,
     selectedEmail: null,
-    selectedEmailIds: new Set(),
+    selectedEmailKeys: new Set(),
     selectedKeyword: null,
     expandedThreadIds: new Set(),
     threadEmailsCache: new Map(),
@@ -1517,41 +1531,42 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   setSearchQuery: (query) => set({ searchQuery: query }),
   setQuota: (quota) => set({ quota }),
 
-  toggleEmailSelection: (emailId) => {
-    const { selectedEmailIds } = get();
-    const newSelection = new Set(selectedEmailIds);
-    if (newSelection.has(emailId)) {
-      newSelection.delete(emailId);
+  toggleEmailSelection: (email) => {
+    const key = emailKeyFor(email);
+    const { selectedEmailKeys } = get();
+    const newSelection = new Set(selectedEmailKeys);
+    if (newSelection.has(key)) {
+      newSelection.delete(key);
     } else {
-      newSelection.add(emailId);
+      newSelection.add(key);
     }
-    set({ selectedEmailIds: newSelection, lastSelectedEmailId: emailId });
+    set({ selectedEmailKeys: newSelection, lastSelectedEmailKey: key });
   },
 
-  selectRangeEmails: (targetEmailId) => {
-    const { emails, lastSelectedEmailId, selectedEmailIds } = get();
-    const anchorId = lastSelectedEmailId || emails[0]?.id;
-    if (!anchorId) return;
-    const anchorIndex = emails.findIndex(e => e.id === anchorId);
-    const targetIndex = emails.findIndex(e => e.id === targetEmailId);
+  selectRangeEmails: (target) => {
+    const { emails, lastSelectedEmailKey, selectedEmailKeys } = get();
+    const anchorKey = lastSelectedEmailKey || (emails[0] && emailKeyFor(emails[0]));
+    if (!anchorKey) return;
+    const anchorIndex = emails.findIndex(e => emailKeyFor(e) === anchorKey);
+    const targetKey = emailKeyFor(target);
+    const targetIndex = emails.findIndex(e => emailKeyFor(e) === targetKey);
     if (anchorIndex === -1 || targetIndex === -1) return;
     const start = Math.min(anchorIndex, targetIndex);
     const end = Math.max(anchorIndex, targetIndex);
-    const newSelection = new Set(selectedEmailIds);
+    const newSelection = new Set(selectedEmailKeys);
     for (let i = start; i <= end; i++) {
-      newSelection.add(emails[i].id);
+      newSelection.add(emailKeyFor(emails[i]));
     }
-    set({ selectedEmailIds: newSelection });
+    set({ selectedEmailKeys: newSelection });
   },
 
   selectAllEmails: () => {
     const { emails } = get();
-    const allIds = new Set(emails.map(e => e.id));
-    set({ selectedEmailIds: allIds });
+    set({ selectedEmailKeys: new Set(emails.map(emailKeyFor)) });
   },
 
   clearSelection: () => {
-    set({ selectedEmailIds: new Set(), lastSelectedEmailId: null });
+    set({ selectedEmailKeys: new Set(), lastSelectedEmailKey: null });
   },
 
   // JMAP operations
@@ -2508,9 +2523,10 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         return {
           emails: state.emails.filter(e => !idSet.has(e.id)),
           selectedEmail: state.selectedEmail && idSet.has(state.selectedEmail.id) ? null : state.selectedEmail,
-          selectedEmailIds: (() => {
-            const next = new Set(state.selectedEmailIds);
-            for (const id of idSet) next.delete(id);
+          selectedEmailKeys: (() => {
+            const next = new Set(state.selectedEmailKeys);
+            // Keys, not ids: drop exactly the emails leaving the list.
+            for (const e of state.emails) if (idSet.has(e.id)) next.delete(emailKeyFor(e));
             return next;
           })(),
           ...patch,
@@ -2601,9 +2617,9 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
           state.selectedEmail && movedSet.has(state.selectedEmail.id)
             ? null
             : state.selectedEmail,
-        selectedEmailIds: (() => {
-          const next = new Set(state.selectedEmailIds);
-          for (const id of movedIds) next.delete(id);
+        selectedEmailKeys: (() => {
+          const next = new Set(state.selectedEmailKeys);
+          for (const e of state.emails) if (movedSet.has(e.id)) next.delete(emailKeyFor(e));
           return next;
         })(),
         isLoading: false,
@@ -2673,8 +2689,11 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       const removedEmailIds = new Set(threadEmailIds);
       set((currentState) => {
         const nextSelectedEmail = getNextSelectedEmailAfterRemoval(currentState, removedEmailIds);
+        const removedKeys = new Set(
+          currentState.emails.filter(e => removedEmailIds.has(e.id)).map(emailKeyFor)
+        );
         const nextSelectedEmailIds = new Set(
-          Array.from(currentState.selectedEmailIds).filter(id => !removedEmailIds.has(id))
+          Array.from(currentState.selectedEmailKeys).filter(key => !removedKeys.has(key))
         );
         const nextExpandedThreadIds = new Set(currentState.expandedThreadIds);
         nextExpandedThreadIds.delete(threadKeyFor(email));
@@ -2684,7 +2703,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         return {
           emails: currentState.emails.filter(currentEmail => !removedEmailIds.has(currentEmail.id)),
           selectedEmail: nextSelectedEmail,
-          selectedEmailIds: nextSelectedEmailIds,
+          selectedEmailKeys: nextSelectedEmailIds,
           expandedThreadIds: nextExpandedThreadIds,
           threadEmailsCache: nextThreadEmailsCache,
         };
@@ -3002,21 +3021,24 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
 
   // Batch operations
   batchMarkAsRead: async (client, read) => {
-    const { selectedEmailIds, emails } = get();
-    if (selectedEmailIds.size === 0) return;
+    const { selectedEmailKeys, emails } = get();
+    if (selectedEmailKeys.size === 0) return;
 
     set({ isLoading: true, error: null });
     try {
-      const emailIdsArray = Array.from(selectedEmailIds);
+      // The selection is keyed by owning account; JMAP takes the bare ids of
+      // exactly those emails, never the keys and never a lookup by id (which
+      // is what let a namesake in another account ride along).
+      const selectedEmails = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
+      const emailIdsArray = selectedEmails.map(e => e.id);
 
       if (isAggregateListView()) {
         // Group by owning JMAP account; dispatch through the reaching login client.
         const bySource = new Map<string, { clientAccountId?: string; ids: string[] }>();
-        for (const emailId of emailIdsArray) {
-          const email = emails.find(e => e.id === emailId);
-          const key = email?.sourceAccountId || '__default__';
-          if (!bySource.has(key)) bySource.set(key, { clientAccountId: email?.sourceClientAccountId, ids: [] });
-          bySource.get(key)!.ids.push(emailId);
+        for (const email of selectedEmails) {
+          const key = email.sourceAccountId || '__default__';
+          if (!bySource.has(key)) bySource.set(key, { clientAccountId: email.sourceClientAccountId, ids: [] });
+          bySource.get(key)!.ids.push(email.id);
         }
 
         const promises = Array.from(bySource.entries()).map(async ([sourceAccountId, { clientAccountId, ids }]) => {
@@ -3036,13 +3058,13 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
 
       // Update local state
       const updatedEmails = emails.map(email =>
-        selectedEmailIds.has(email.id)
+        selectedEmailKeys.has(emailKeyFor(email))
           ? { ...email, keywords: { ...email.keywords, $seen: read } }
           : email
       );
 
       // Update mailbox counters per the email's own account list (#281).
-      const affectedEmails = emails.filter(e => selectedEmailIds.has(e.id));
+      const affectedEmails = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
       const mailboxPatch = applyBatchMailboxCounterUpdate(get(), affectedEmails, (mailbox, group) => {
         let deltaUnread = 0;
         for (const email of group as Email[]) {
@@ -3081,7 +3103,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         ...mailboxPatch,
         tagCounts,
         retainedInViewIds,
-        selectedEmailIds: new Set(),
+        selectedEmailKeys: new Set(),
         isLoading: false
       });
     } catch (error) {
@@ -3093,13 +3115,17 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   },
 
   batchDelete: async (client, permanent = false) => {
-    const { selectedEmailIds, emails, selectedMailbox } = get();
+    const { selectedEmailKeys, emails, selectedMailbox } = get();
     const mailboxes = resolveActionMailboxes();
-    if (selectedEmailIds.size === 0) return;
+    if (selectedEmailKeys.size === 0) return;
 
     set({ isLoading: true, error: null });
     try {
-      const emailIdsArray = Array.from(selectedEmailIds);
+      // The selection is keyed by owning account; JMAP takes the bare ids of
+      // exactly those emails, never the keys and never a lookup by id (which
+      // is what let a namesake in another account ride along).
+      const selectedEmails = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
+      const emailIdsArray = selectedEmails.map(e => e.id);
 
       // Determine if the current folder forces permanent deletion.
       const currentMailbox = mailboxes.find(m => m.id === selectedMailbox);
@@ -3183,7 +3209,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
           set({
             emails: remainingEmails,
             ...mailboxPatch,
-            selectedEmailIds: new Set(),
+            selectedEmailKeys: new Set(),
             selectedEmail: null,
             isLoading: false,
             error: 'Some emails could not be moved: trash folder missing for one or more accounts',
@@ -3193,16 +3219,16 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       }
 
       // Remove deleted emails from local state
-      const remainingEmails = emails.filter(e => !selectedEmailIds.has(e.id));
+      const remainingEmails = emails.filter(e => !selectedEmailKeys.has(emailKeyFor(e)));
 
       // Update mailbox counters per the email's own account list (#281).
-      const deletedEmails = emails.filter(e => selectedEmailIds.has(e.id));
+      const deletedEmails = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
       const mailboxPatch = applyBatchMailboxCounterUpdate(get(), deletedEmails, applyDeleteCounters);
 
       set({
         emails: remainingEmails,
         ...mailboxPatch,
-        selectedEmailIds: new Set(),
+        selectedEmailKeys: new Set(),
         selectedEmail: null,
         isLoading: false
       });
@@ -3215,23 +3241,26 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   },
 
   batchMoveToMailbox: async (client, toMailboxId) => {
-    const { selectedEmailIds, emails } = get();
-    if (selectedEmailIds.size === 0) return;
+    const { selectedEmailKeys, emails } = get();
+    if (selectedEmailKeys.size === 0) return;
 
     set({ isLoading: true, error: null });
     try {
-      const emailIdsArray = Array.from(selectedEmailIds);
+      // The selection is keyed by owning account; JMAP takes the bare ids of
+      // exactly those emails, never the keys and never a lookup by id (which
+      // is what let a namesake in another account ride along).
+      const selectedEmails = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
+      const emailIdsArray = selectedEmails.map(e => e.id);
 
       if (isAggregateListView()) {
         // Group by owning JMAP account; dispatch through the reaching login client.
         const destMailbox = resolveActionMailboxes().find(mb => mb.id === toMailboxId);
         const jmapDestId = destMailbox?.originalId || toMailboxId;
         const bySource = new Map<string, { clientAccountId?: string; ids: string[] }>();
-        for (const emailId of emailIdsArray) {
-          const email = emails.find(e => e.id === emailId);
-          const key = email?.sourceAccountId || '__default__';
-          if (!bySource.has(key)) bySource.set(key, { clientAccountId: email?.sourceClientAccountId, ids: [] });
-          bySource.get(key)!.ids.push(emailId);
+        for (const email of selectedEmails) {
+          const key = email.sourceAccountId || '__default__';
+          if (!bySource.has(key)) bySource.set(key, { clientAccountId: email.sourceClientAccountId, ids: [] });
+          bySource.get(key)!.ids.push(email.id);
         }
 
         const promises = Array.from(bySource.entries()).map(async ([sourceAccountId, { clientAccountId, ids }]) => {
@@ -3254,11 +3283,11 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       }
 
       // Update local state - remove from current view since they moved
-      const remainingEmails = emails.filter(e => !selectedEmailIds.has(e.id));
+      const remainingEmails = emails.filter(e => !selectedEmailKeys.has(emailKeyFor(e)));
 
       set({
         emails: remainingEmails,
-        selectedEmailIds: new Set(),
+        selectedEmailKeys: new Set(),
         isLoading: false
       });
 
@@ -3275,9 +3304,9 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   },
 
   batchArchive: async (client) => {
-    const { selectedEmailIds, emails } = get();
+    const { selectedEmailKeys, emails } = get();
     const mailboxes = resolveActionMailboxes();
-    if (selectedEmailIds.size === 0) return;
+    if (selectedEmailKeys.size === 0) return;
 
     // Scope the archive folder to the viewed shared/group account (if any) so the
     // move lands on the owner account, not the user's own archive (which appears
@@ -3292,7 +3321,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     const mode = useSettingsStore.getState().archiveMode;
     const archiveId = archiveMailbox.originalId || archiveMailbox.id;
 
-    const selected = emails.filter(e => selectedEmailIds.has(e.id));
+    const selected = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
     if (selected.length === 0) return;
 
     set({ isLoading: true, error: null });
@@ -3305,8 +3334,8 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         archiveMailbox.accountId,
       );
 
-      const remaining = emails.filter(e => !selectedEmailIds.has(e.id));
-      set({ emails: remaining, selectedEmailIds: new Set(), isLoading: false });
+      const remaining = emails.filter(e => !selectedEmailKeys.has(emailKeyFor(e)));
+      set({ emails: remaining, selectedEmailKeys: new Set(), isLoading: false });
 
       // Refresh the active or viewed account's mailbox cache after the
       // archive (a year/month archive can create new sub-folders).
@@ -3546,7 +3575,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         return {
           emails: state.emails.filter(e => !emailIds.includes(e.id)),
           selectedEmail: emailIds.includes(state.selectedEmail?.id || '') ? null : state.selectedEmail,
-          selectedEmailIds: new Set(),
+          selectedEmailKeys: new Set(),
           ...patch,
         };
       });
@@ -3610,7 +3639,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         return {
           emails: state.emails.filter(e => !emailIds.includes(e.id)),
           selectedEmail: emailIds.includes(state.selectedEmail?.id || '') ? null : state.selectedEmail,
-          selectedEmailIds: new Set(),
+          selectedEmailKeys: new Set(),
           ...patch,
         };
       });
@@ -4703,7 +4732,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       scheduledAccountScope: isScheduledView ? accountScope : null,
       selectedMailbox: isScheduledView ? VIRTUAL_SCHEDULED_MAILBOX_ID : leavingScheduled ? "" : state.selectedMailbox,
       selectedEmail: leavingScheduled ? null : state.selectedEmail,
-      selectedEmailIds: leavingScheduled ? new Set<string>() : state.selectedEmailIds,
+      selectedEmailKeys: leavingScheduled ? new Set<string>() : state.selectedEmailKeys,
       // Search is unavailable in the scheduled view (the input is disabled there).
       // Reset any active search when entering it so a stale query can't linger or
       // re-run when the user leaves again.
@@ -4837,7 +4866,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       await client.deleteEmail(emailId);
       set(state => ({
         selectedEmail: state.selectedEmail?.id === emailId ? null : state.selectedEmail,
-        selectedEmailIds: new Set(Array.from(state.selectedEmailIds).filter(id => id !== emailId)),
+        selectedEmailKeys: dropFromSelection(state, e => e.id === emailId),
       }));
     }
     if (get().pendingUndoSend?.submissionId === submissionId) {
@@ -4857,7 +4886,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       await client.deleteEmail(email.id);
       set(state => ({
         selectedEmail: state.selectedEmail?.id === email.id ? null : state.selectedEmail,
-        selectedEmailIds: new Set(Array.from(state.selectedEmailIds).filter(id => id !== email.id)),
+        selectedEmailKeys: dropFromSelection(state, e => e.id === email.id),
       }));
       await get().fetchScheduledEmails(client);
       return null;
@@ -4907,7 +4936,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       await client.deleteEmail(pending.emailId);
       set(state => ({
         selectedEmail: state.selectedEmail?.id === pending.emailId ? null : state.selectedEmail,
-        selectedEmailIds: new Set(Array.from(state.selectedEmailIds).filter(id => id !== pending.emailId)),
+        selectedEmailKeys: dropFromSelection(state, e => e.id === pending.emailId),
       }));
     } else if (pending.emailId) {
       const mailboxes = get().mailboxes.length > 0 ? get().mailboxes : await client.getMailboxes();

From f2d49f4060a556668cb3ace9615ae3762739fd7d Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Wed, 30 Sep 2026 08:44:38 +0200
Subject: [PATCH 03/23] fix: carry the inbox-only choice into bulk push and use
 the shared icons

Upstream now requires inboxOnly when enabling push and replaced lucide-react
with the shared icon module; the bulk path had neither.
---
 components/settings/multi-account-push.tsx | 5 +++--
 lib/__tests__/web-push.test.ts             | 4 ++--
 lib/web-push.ts                            | 4 +++-
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/components/settings/multi-account-push.tsx b/components/settings/multi-account-push.tsx
index fb0038d20..cb025b3e7 100644
--- a/components/settings/multi-account-push.tsx
+++ b/components/settings/multi-account-push.tsx
@@ -2,11 +2,12 @@
 
 import { useCallback, useEffect, useState } from 'react';
 import { useTranslations } from 'next-intl';
-import { Loader2 } from 'lucide-react';
+import { Loader2 } from '@/components/icons';
 import { Button } from '@/components/ui/button';
 import { SettingsSection } from './settings-section';
 import { useAccountStore } from '@/stores/account-store';
 import { useAuthStore } from '@/stores/auth-store';
+import { useSettingsStore } from '@/stores/settings-store';
 import { disableWebPush, enableWebPushForAccounts, isWebPushEnabled, isWebPushSupported } from '@/lib/web-push';
 
 /**
@@ -55,7 +56,7 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
       if (action === 'enable') {
         const outcome = await enableWebPushForAccounts(
           targets.map(a => ({ accountId: a.id, client: auth.getClientForAccount(a.id)!, accountLabel: a.username })),
-          { relayBaseUrl },
+          { relayBaseUrl, inboxOnly: useSettingsStore.getState().pushNotifyInboxOnly },
         );
         setNotice(outcome.failed.length
           ? t('result_partial', { enabled: outcome.enabled.length, failed: outcome.failed.length })
diff --git a/lib/__tests__/web-push.test.ts b/lib/__tests__/web-push.test.ts
index f3bbc0002..03b450ec7 100644
--- a/lib/__tests__/web-push.test.ts
+++ b/lib/__tests__/web-push.test.ts
@@ -617,7 +617,7 @@ describe('enableWebPushForAccounts', () => {
     const result = await enableWebPushForAccounts([
       { accountId: 'a', client: first, accountLabel: 'one' },
       { accountId: 'b', client: second, accountLabel: 'two' },
-    ], { relayBaseUrl: RELAY });
+    ], { relayBaseUrl: RELAY, inboxOnly: false });
 
     expect(result.enabled).toEqual(['a', 'b']);
     expect(result.failed).toEqual([]);
@@ -637,7 +637,7 @@ describe('enableWebPushForAccounts', () => {
     const result = await enableWebPushForAccounts([
       { accountId: 'a', client: first },
       { accountId: 'b', client: second },
-    ], { relayBaseUrl: RELAY });
+    ], { relayBaseUrl: RELAY, inboxOnly: false });
 
     expect(result.enabled).toEqual([]);
     expect(result.failed.map(f => f.accountId)).toEqual(['a', 'b']);
diff --git a/lib/web-push.ts b/lib/web-push.ts
index 23f53a0a5..f5c51acf7 100644
--- a/lib/web-push.ts
+++ b/lib/web-push.ts
@@ -791,7 +791,8 @@ export interface BulkWebPushResult {
  */
 export async function enableWebPushForAccounts(
   targets: BulkWebPushTarget[],
-  options: { relayBaseUrl?: string; forceRecreate?: boolean } = {},
+  // inboxOnly mirrors settings-store's pushNotifyInboxOnly, as for a single account.
+  options: { relayBaseUrl?: string; forceRecreate?: boolean; inboxOnly: boolean },
 ): Promise<BulkWebPushResult> {
   const result: BulkWebPushResult = { enabled: [], failed: [] };
   let browserRefusal: unknown;
@@ -806,6 +807,7 @@ export async function enableWebPushForAccounts(
         relayBaseUrl: options.relayBaseUrl,
         accountLabel: target.accountLabel,
         forceRecreate: options.forceRecreate,
+        inboxOnly: options.inboxOnly,
       });
       result.enabled.push(target.accountId);
     } catch (error) {

From 4ee234b7c3e984254198908333a07d0468b15074 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Wed, 30 Sep 2026 09:02:58 +0200
Subject: [PATCH 04/23] fix: resolve selection keys to ids before the batch
 spam actions

batchMarkAsSpam and batchUndoSpam take the bare ids of the viewed account,
but were handed the selection keys. Those match only while no row carries
a source account; mail of a shared account was silently left out.
---
 components/email/email-list.tsx | 8 ++++----
 components/mail/mail-app.tsx    | 6 ++++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/components/email/email-list.tsx b/components/email/email-list.tsx
index 825185f40..110d6b54b 100644
--- a/components/email/email-list.tsx
+++ b/components/email/email-list.tsx
@@ -16,7 +16,7 @@ import { useEmailStore, ArchiveMailboxNotFoundError } from "@/stores/email-store
 import { useAuthStore } from "@/stores/auth-store";
 import { useSettingsStore } from "@/stores/settings-store";
 import { useUIStore } from "@/stores/ui-store";
-import { groupEmailsByThread, sortThreadGroups, threadKeyFor } from "@/lib/thread-utils";
+import { emailKeyFor, groupEmailsByThread, sortThreadGroups, threadKeyFor } from "@/lib/thread-utils";
 import { useContextMenu } from "@/hooks/use-context-menu";
 import { useConfirmDialog } from "@/hooks/use-confirm-dialog";
 import { useTranslations } from "next-intl";
@@ -281,7 +281,7 @@ export function EmailList({
     if (!client || isProcessing) return;
     setIsProcessing(true);
     try {
-      const emailIds = Array.from(selectedEmailKeys);
+      const emailIds = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
       await batchUndoSpam(client, emailIds);
       toast.success(tSpam('toast_not_spam_batch', { count: emailIds.length }));
     } catch {
@@ -711,7 +711,7 @@ export function EmailList({
           }}
           onBatchMarkAsSpam={async () => {
             if (client) {
-              const emailIds = Array.from(selectedEmailKeys);
+              const emailIds = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
               try {
                 await batchMarkAsSpam(client, emailIds);
                 toast.success(
@@ -724,7 +724,7 @@ export function EmailList({
           }}
           onBatchUndoSpam={async () => {
             if (client) {
-              const emailIds = Array.from(selectedEmailKeys);
+              const emailIds = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
               try {
                 await batchUndoSpam(client, emailIds);
                 toast.success(
diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index 81b94afba..ee7a4aa4c 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -56,7 +56,7 @@ import { debug } from "@/lib/debug";
 import { playNotificationSound } from "@/lib/notification-sound";
 import { cn, getMailboxPath } from "@/lib/utils";
 import { localizeMailboxName } from "@/lib/mailbox-label";
-import { KEYWORD_PREFIX, KEYWORD_PREFIX_LEGACY, groupEmailsByThread, threadKeyFor } from "@/lib/thread-utils";
+import { KEYWORD_PREFIX, KEYWORD_PREFIX_LEGACY, emailKeyFor, groupEmailsByThread, threadKeyFor } from "@/lib/thread-utils";
 import { resolveThreadRoute } from "@/lib/thread-routing";
 import {
   ErrorBoundary,
@@ -788,7 +788,9 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       if (['sent', 'drafts', 'scheduled'].includes(currentMailbox?.role || '')) return;
       const isInJunk = currentMailbox?.role === 'junk';
       if (selectedEmailKeys.size > 0 && client) {
-        const ids = Array.from(selectedEmailKeys);
+        // The spam actions take bare ids of the viewed account: resolve the
+        // selection keys through the loaded rows.
+        const ids = useEmailStore.getState().emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
         try {
           if (isInJunk) {
             await batchUndoSpam(client, ids);

From 405c0e656ee7202dbc90d7f1440fb41e2a6f0539 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Thu, 1 Oct 2026 07:36:37 +0200
Subject: [PATCH 05/23] fix(push): show each login's real push state in the
 all-accounts panel

Push state is stored under the JMAP account id the server assigned
(enableWebPush keys it on client.getAccountId()), but the all-accounts
panel looked it up under the login's own id, so every account read
"notifications off" even right after enabling them. Read it back
under the JMAP account id.
---
 .../__tests__/multi-account-push.test.tsx     | 47 +++++++++++++++++++
 components/settings/multi-account-push.tsx    |  7 ++-
 2 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 components/settings/__tests__/multi-account-push.test.tsx

diff --git a/components/settings/__tests__/multi-account-push.test.tsx b/components/settings/__tests__/multi-account-push.test.tsx
new file mode 100644
index 000000000..1c3f01eaf
--- /dev/null
+++ b/components/settings/__tests__/multi-account-push.test.tsx
@@ -0,0 +1,47 @@
+import { render, waitFor } from '@testing-library/react';
+import { describe, it, expect, vi } from 'vitest';
+import { MultiAccountPushSettings } from '../multi-account-push';
+import { useAccountStore } from '@/stores/account-store';
+import { useAuthStore } from '@/stores/auth-store';
+import * as webPush from '@/lib/web-push';
+
+vi.mock('next-intl', () => ({
+  useTranslations: () => (key: string) => key,
+}));
+
+vi.mock('../settings-section', async (importOriginal) => ({
+  ...(await importOriginal<typeof import('../settings-section')>()),
+  SettingsSection: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+}));
+
+// Push state is stored under the JMAP account id the server assigned: only
+// "jmap-a" has a registration here.
+vi.mock('@/lib/web-push', () => ({
+  isWebPushSupported: () => true,
+  isWebPushEnabled: vi.fn(async (id: string) => id === 'jmap-a'),
+  enableWebPushForAccounts: vi.fn(),
+  disableWebPush: vi.fn(),
+}));
+
+describe('MultiAccountPushSettings', () => {
+  it('reads each login\'s push state under its JMAP account id', async () => {
+    const clients: Record<string, { getAccountId: () => string }> = {
+      'a@mail.example.com': { getAccountId: () => 'jmap-a' },
+      'b@mail.example.com': { getAccountId: () => 'jmap-b' },
+    };
+    useAccountStore.setState({
+      accounts: [
+        { id: 'a@mail.example.com', username: 'a', email: 'a@example.com', isConnected: true },
+        { id: 'b@mail.example.com', username: 'b', email: 'b@example.com', isConnected: true },
+      ] as never,
+    });
+    useAuthStore.setState({ getClientForAccount: ((id: string) => clients[id]) as never });
+
+    const { container } = render(<MultiAccountPushSettings />);
+
+    await waitFor(() => expect(container.textContent).toContain('a@example.com · state_on'));
+    expect(container.textContent).toContain('b@example.com · state_off');
+    expect(webPush.isWebPushEnabled).toHaveBeenCalledWith('jmap-a');
+    expect(webPush.isWebPushEnabled).not.toHaveBeenCalledWith('a@mail.example.com');
+  });
+});
diff --git a/components/settings/multi-account-push.tsx b/components/settings/multi-account-push.tsx
index cb025b3e7..d431a36b7 100644
--- a/components/settings/multi-account-push.tsx
+++ b/components/settings/multi-account-push.tsx
@@ -31,8 +31,13 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
   const connected = accounts.filter(a => a.isConnected && useAuthStore.getState().getClientForAccount(a.id));
 
   const refresh = useCallback(async () => {
+    // Push state is stored under the JMAP account id the server assigned (see
+    // enableWebPush), not under the login's own id: read it back the same way.
     const entries = await Promise.all(
-      useAccountStore.getState().accounts.map(async a => [a.id, await isWebPushEnabled(a.id)] as const),
+      useAccountStore.getState().accounts.map(async (a) => {
+        const jmapAccountId = useAuthStore.getState().getClientForAccount(a.id)?.getAccountId();
+        return [a.id, jmapAccountId ? await isWebPushEnabled(jmapAccountId) : false] as const;
+      }),
     );
     setEnabled(Object.fromEntries(entries));
   }, []);

From 7739f1aaaab2cb8071e9d0f9b9179fd7cbcd0c89 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Thu, 1 Oct 2026 10:22:57 +0200
Subject: [PATCH 06/23] fix(settings): keep the merged mailbox when switching
 to another account

Switching account loads that account's synced settings, and the views
that span every login - the unified mailbox, its cross-account scope and
the All mail / Unread / Starred entries - came along with them. An
account whose stored settings predated the merged mailbox turned it off
as soon as it became active, so the folders of every account were only
visible from the other one.

Once a device holds several logins those views are its own choice and
an account switch leaves them alone. A device's first login still takes
them from the server, and they are still saved with the settings.
---
 ...settings-store-cross-account-views.test.ts | 54 +++++++++++++++++++
 stores/settings-store.ts                      | 29 +++++++++-
 2 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 stores/__tests__/settings-store-cross-account-views.test.ts

diff --git a/stores/__tests__/settings-store-cross-account-views.test.ts b/stores/__tests__/settings-store-cross-account-views.test.ts
new file mode 100644
index 000000000..f24753de4
--- /dev/null
+++ b/stores/__tests__/settings-store-cross-account-views.test.ts
@@ -0,0 +1,54 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const apiFetch = vi.hoisted(() => vi.fn());
+vi.mock('@/lib/browser-navigation', () => ({ apiFetch }));
+
+import { useSettingsStore } from '../settings-store';
+import { useAccountStore } from '../account-store';
+
+// An account whose stored settings predate the merged mailbox.
+const STORED = { enableUnifiedMailbox: false, unifiedCrossAccount: false, enableCrossAllView: false, sendDelaySeconds: 30 };
+
+function serverAnswers(settings: Record<string, unknown>) {
+  apiFetch.mockResolvedValue(new Response(JSON.stringify({ settings }), {
+    status: 200,
+    headers: { 'Content-Type': 'application/json' },
+  }));
+}
+
+describe('views spanning every account across an account switch', () => {
+  beforeEach(() => {
+    apiFetch.mockReset();
+    useSettingsStore.getState().disableSync();
+    useSettingsStore.setState({
+      enableUnifiedMailbox: true,
+      unifiedCrossAccount: true,
+      enableCrossAllView: true,
+      sendDelaySeconds: 0,
+    });
+  });
+
+  it('keeps the device\'s merged-mailbox choice when another of its logins loads its settings', async () => {
+    useAccountStore.setState({ accounts: [{ id: 'a' }, { id: 'b' }] as never });
+    serverAnswers(STORED);
+
+    await useSettingsStore.getState().loadFromServer('b@example.com', 'https://mail-b.example.com');
+
+    const s = useSettingsStore.getState();
+    expect(s.enableUnifiedMailbox).toBe(true);
+    expect(s.unifiedCrossAccount).toBe(true);
+    expect(s.enableCrossAllView).toBe(true);
+    // Everything else still follows the account.
+    expect(s.sendDelaySeconds).toBe(30);
+  });
+
+  it('takes them from the server on a device\'s first login', async () => {
+    useAccountStore.setState({ accounts: [{ id: 'a' }] as never });
+    serverAnswers(STORED);
+
+    await useSettingsStore.getState().loadFromServer('a@example.com', 'https://mail-a.example.com');
+
+    expect(useSettingsStore.getState().enableUnifiedMailbox).toBe(false);
+    expect(useSettingsStore.getState().unifiedCrossAccount).toBe(false);
+  });
+});
diff --git a/stores/settings-store.ts b/stores/settings-store.ts
index 971a13e67..68cabc39a 100644
--- a/stores/settings-store.ts
+++ b/stores/settings-store.ts
@@ -147,6 +147,23 @@ export type ProtocolOpenMode = 'active-session' | 'new-tab';
  */
 const DEVICE_LOCAL_SETTING_KEYS = new Set<string>(['proInterface']);
 
+/**
+ * Settings that shape views spanning every logged-in account. They are synced
+ * with the active account's settings like everything else, but once a device
+ * holds several logins they are that device's choice: switching to another
+ * account must not turn the merged mailbox off just because that account's
+ * stored settings predate it. A first login on a device still takes them from
+ * the server.
+ */
+const CROSS_ACCOUNT_VIEW_KEYS = new Set<string>([
+  'enableUnifiedMailbox',
+  'includeGroupInUnified',
+  'unifiedCrossAccount',
+  'enableCrossUnreadView',
+  'enableCrossStarredView',
+  'enableCrossAllView',
+]);
+
 export type HoverAction = 'delete' | 'star' | 'markRead' | 'archive' | 'tag' | 'spam';
 /** Action fired by a mobile list-row swipe. 'none' disables that direction. */
 export type SwipeAction = 'none' | 'archive' | 'delete' | 'markRead' | 'star' | 'spam';
@@ -513,7 +530,7 @@ interface SettingsState {
   ) => void;
   resetToDefaults: () => void;
   exportSettings: () => string;
-  importSettings: (json: string, opts?: { serverAccountId?: string }) => boolean;
+  importSettings: (json: string, opts?: { serverAccountId?: string; keepCrossAccountViews?: boolean }) => boolean;
 
   // Folder icons
   setFolderIcon: (mailboxId: string, icon: string) => void;
@@ -905,7 +922,7 @@ export const useSettingsStore = create<SettingsState>()(
         return JSON.stringify(settings, null, 2);
       },
 
-      importSettings: (json: string, opts?: { serverAccountId?: string }) => {
+      importSettings: (json: string, opts?: { serverAccountId?: string; keepCrossAccountViews?: boolean }) => {
         try {
           const settings = JSON.parse(json);
 
@@ -957,6 +974,9 @@ export const useSettingsStore = create<SettingsState>()(
               if (DEVICE_LOCAL_SETTING_KEYS.has(key)) {
                 return;
               }
+              if (opts?.keepCrossAccountViews && CROSS_ACCOUNT_VIEW_KEYS.has(key)) {
+                return;
+              }
               // Per-account maps (accountId -> value) live in every account's
               // synced settings blob, so a per-account server load must NOT
               // replace the whole map - each account's server is authoritative
@@ -1168,11 +1188,16 @@ export const useSettingsStore = create<SettingsState>()(
             return false;
           }
           if (settings && typeof settings === 'object') {
+            // With several logins on this device, the views spanning them stay
+            // as the device has them (see CROSS_ACCOUNT_VIEW_KEYS).
+            const { useAccountStore } = await import('./account-store');
+            const keepCrossAccountViews = useAccountStore.getState().accounts.length > 1;
             isLoadingFromServer = true;
             // Merge (not replace) per-account maps for the account being loaded,
             // so multi-account logins don't clobber each other by login order.
             get().importSettings(JSON.stringify(settings), {
               serverAccountId: generateAccountId(username, serverUrl),
+              keepCrossAccountViews,
             });
             isLoadingFromServer = false;
             syncLog('Settings loaded from server successfully');

From d632956231b83d05b4332ab27db0157d33b9ce00 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Mon, 5 Oct 2026 10:36:20 +0200
Subject: [PATCH 07/23] feat: add Mountain View, an optional alternative layout

Add an "Interface layout" setting at the top of Settings > Layout with two
options, Default and Mountain View. Default is the existing layout and stays
the default, so nothing changes unless a user opts in.

Mountain View rearranges the chrome while keeping the theme's colours, icons
and type:

- desktop: a top bar with a wide search field (filters drop from the field),
  an apps grid and the account avatar instead of the left app rail; flat
  navigation with Starred under Inbox and the rest behind "More"; a Compose
  pill; one list toolbar with select-all, refresh, overflow menu, a 1-N of
  total range and the batch actions; rows led by a checkbox and a star; an
  icon-only message toolbar with Reply / Reply all / Forward under the
  message; compose in a docked window; an account popover with per-account
  unread counts; j/k cursor, x to select and g-sequences
- phone: rounded search header, compact rows with the star on the preview
  line, and Reply / Reply all / Forward at the end of a message instead of
  the bottom action bar

It is one setting (`interfaceLayout`), written to a data attribute on <html>
that keys a block of CSS tokens in globals.css, plus a few components gated
on the flag. The mail layout in force is derived (effectiveMailLayout), so
the user's saved mail layout is never rewritten. The setting is listed in
the admin policy tab, and the new strings are translated in all locales.

Includes unit tests and a Playwright smoke test against a running instance
(scripts/mountain-view-smoke/).
---
 app/(main)/admin/_tabs/policy.tsx             |   1 +
 app/globals.css                               | 107 ++++
 .../email/__tests__/mv-list-toolbar.test.tsx  | 158 ++++++
 .../email/__tests__/thread-list-item.test.tsx |  58 +-
 components/email/email-list.tsx               |  11 +-
 components/email/email-viewer.tsx             | 101 +++-
 components/email/mv-compose-window.tsx        |  76 +++
 components/email/mv-list-toolbar.tsx          | 529 ++++++++++++++++++
 components/email/thread-list-item.tsx         | 260 +++++++--
 components/icons/index.ts                     |   1 +
 components/keyboard-shortcuts-modal.tsx       |  17 +-
 .../account-switcher-mountain-view.test.tsx   | 121 ++++
 .../sidebar-mountain-view-flat-list.test.tsx  | 136 +++++
 components/layout/account-switcher.tsx        | 152 ++++-
 components/layout/mobile-header.tsx           |  27 +-
 components/layout/mv-top-bar.tsx              | 335 +++++++++++
 components/layout/navigation-rail.tsx         |  18 +-
 components/layout/sidebar.tsx                 | 140 ++++-
 components/mail/mail-app.tsx                  | 347 ++++++++----
 .../__tests__/filter-panel-host.test.tsx      |  55 ++
 components/search/filter-panel-host.tsx       |  83 +++
 components/settings/layout-settings.tsx       |  18 +-
 components/settings/reading-settings.tsx      |   4 +-
 hooks/use-effective-mail-layout.ts            |   8 +
 hooks/use-keyboard-shortcuts.ts               |  84 ++-
 hooks/use-pro-multi-account-mailboxes.ts      |  11 +-
 lib/__tests__/account-inbox-unread.test.ts    |  64 +++
 lib/account-inbox-unread.ts                   |  35 ++
 locales/ar/common.json                        |  18 +-
 locales/ca/common.json                        |  18 +-
 locales/cs/common.json                        |  18 +-
 locales/da/common.json                        |  18 +-
 locales/de/common.json                        |  18 +-
 locales/en/common.json                        |  18 +-
 locales/es/common.json                        |  18 +-
 locales/fa/common.json                        |  18 +-
 locales/fr/common.json                        |  18 +-
 locales/he/common.json                        |  18 +-
 locales/hu/common.json                        |  18 +-
 locales/it/common.json                        |  18 +-
 locales/ja/common.json                        |  18 +-
 locales/ko/common.json                        |  18 +-
 locales/lv/common.json                        |  18 +-
 locales/mn/common.json                        |  18 +-
 locales/nb/common.json                        |  18 +-
 locales/nl/common.json                        |  18 +-
 locales/pl/common.json                        |  18 +-
 locales/pt/common.json                        |  18 +-
 locales/ro/common.json                        |  18 +-
 locales/ru/common.json                        |  18 +-
 locales/sk/common.json                        |  18 +-
 locales/tr/common.json                        |  18 +-
 locales/uk/common.json                        |  18 +-
 locales/zh-TW/common.json                     |  18 +-
 locales/zh/common.json                        |  18 +-
 .../mountain-view-smoke.mjs                   | 131 +++++
 .../settings-density-mountain-view.test.ts    |  43 ++
 stores/settings-store.ts                      | 160 ++++--
 58 files changed, 3477 insertions(+), 300 deletions(-)
 create mode 100644 components/email/__tests__/mv-list-toolbar.test.tsx
 create mode 100644 components/email/mv-compose-window.tsx
 create mode 100644 components/email/mv-list-toolbar.tsx
 create mode 100644 components/layout/__tests__/account-switcher-mountain-view.test.tsx
 create mode 100644 components/layout/__tests__/sidebar-mountain-view-flat-list.test.tsx
 create mode 100644 components/layout/mv-top-bar.tsx
 create mode 100644 components/search/__tests__/filter-panel-host.test.tsx
 create mode 100644 components/search/filter-panel-host.tsx
 create mode 100644 hooks/use-effective-mail-layout.ts
 create mode 100644 lib/__tests__/account-inbox-unread.test.ts
 create mode 100644 lib/account-inbox-unread.ts
 create mode 100644 scripts/mountain-view-smoke/mountain-view-smoke.mjs
 create mode 100644 stores/__tests__/settings-density-mountain-view.test.ts

diff --git a/app/(main)/admin/_tabs/policy.tsx b/app/(main)/admin/_tabs/policy.tsx
index 29c1a6a56..b7aeb7c7b 100644
--- a/app/(main)/admin/_tabs/policy.tsx
+++ b/app/(main)/admin/_tabs/policy.tsx
@@ -42,6 +42,7 @@ const FEATURE_GATE_LABELS: Partial<Record<keyof FeatureGates, { label: string; d
 const RESTRICTABLE_SETTINGS = [
   { key: 'fontSize', label: 'Font Size', category: 'Appearance', type: 'enum', allowedValues: ['small', 'medium', 'large'] },
   { key: 'density', label: 'Density', category: 'Appearance', type: 'enum', allowedValues: ['compact', 'regular', 'spacious'] },
+  { key: 'interfaceLayout', label: 'Interface Layout', category: 'Appearance', type: 'enum', allowedValues: ['default', 'mountain-view'] },
   { key: 'animationsEnabled', label: 'Animations', category: 'Appearance', type: 'boolean' },
   { key: 'markAsReadDelay', label: 'Mark as Read Delay', category: 'Email', type: 'number' },
   { key: 'deleteAction', label: 'Delete Action', category: 'Email', type: 'enum', allowedValues: ['trash', 'trash-and-read', 'permanent'] },
diff --git a/app/globals.css b/app/globals.css
index 0817bf6b0..8336675a0 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -910,3 +910,110 @@ optgroup {
 [dir="rtl"] .tabler-icon-layout-sidebar-right {
   transform: scaleX(-1);
 }
+
+/* ==========================================================================
+   Interface layouts
+   --------------------------------------------------------------------------
+   `data-interface-layout` is set on <html> by the settings store
+   (`applyInterfaceLayout`). The default layout declares no overrides, so
+   everything below is additive and switched off by a single attribute.
+   Mountain View sets its own geometry - bar heights, rail widths, pill shapes,
+   row rhythm - while colour, iconography and type keep coming from the active
+   theme.
+   ========================================================================== */
+
+[data-interface-layout="mountain-view"] {
+  --mv-topbar-h: 64px;
+  --mv-rail-w: 72px;
+  --mv-rail-peek-w: 256px;
+  --mv-nav-row-h: 32px;
+  --mv-nav-radius: 9999px;
+  --mv-compose-h: 56px;
+  --mv-search-h: 48px;
+  --mv-search-radius: 8px;
+  --mv-popover-w: 352px;
+  --mv-popover-radius: 28px;
+}
+
+/* Search: a filled 48px field that lifts onto a card while focused, rather
+   than the outlined input the default layout uses. */
+[data-interface-layout="mountain-view"] .mv-topbar input[data-search-input] {
+  height: var(--mv-search-h);
+  border-radius: var(--mv-search-radius);
+  border-color: transparent;
+  background-color: var(--color-muted);
+  padding-inline-start: 3rem;
+  font-size: 1rem;
+}
+
+[data-interface-layout="mountain-view"] .mv-topbar input[data-search-input]:hover {
+  border-color: transparent;
+  background-color: var(--color-accent);
+}
+
+[data-interface-layout="mountain-view"] .mv-topbar input[data-search-input]:focus-visible {
+  background-color: var(--color-background);
+  border-color: transparent;
+  box-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.16), 0 4px 8px 3px rgb(0 0 0 / 0.08);
+}
+
+/* The filter button sits inside the field's trailing end: keep typed text and
+   the clear button clear of it. */
+[data-interface-layout="mountain-view"] .mv-topbar input[data-search-input] {
+  padding-inline-end: 5.5rem;
+}
+
+[data-interface-layout="mountain-view"] .mv-topbar-search > div > form > button {
+  inset-inline-end: 3.25rem;
+}
+
+/* The magnifier sits on the field's baseline grid, one 48px hit area in. */
+[data-interface-layout="mountain-view"] .mv-topbar-search > div > form > svg {
+  inset-inline-start: 1rem;
+  width: 1.25rem;
+  height: 1.25rem;
+}
+
+/* Folder rows: 32px pills flush with the rail's leading edge and rounded only
+   on the trailing side, so the selected label reads as one continuous shape
+   with the rail. The default layout's leading accent stripe goes away with it. */
+[data-interface-layout="mountain-view"] [data-mv-nav-row] {
+  min-height: var(--mv-nav-row-h);
+  margin-inline-end: 12px;
+  padding-inline-end: 16px;
+  border-inline-start-width: 0;
+  border-start-start-radius: 0;
+  border-end-start-radius: 0;
+  border-start-end-radius: var(--mv-nav-radius);
+  border-end-end-radius: var(--mv-nav-radius);
+}
+
+/* Compose: a 56px pill, which shrinks to a circle with the rail. */
+[data-interface-layout="mountain-view"] [data-mv-compose] {
+  height: var(--mv-compose-h);
+  border-radius: var(--mv-nav-radius);
+}
+
+/* The account popover: a wide card with a very round corner, rather
+   than the narrow menu the rail and the sidebar switchers drop. */
+[data-interface-layout="mountain-view"] [data-mv-account-popover] {
+  width: var(--mv-popover-w);
+  border-radius: var(--mv-popover-radius);
+}
+
+/* The advanced filters drop from the search field with a small gap and take
+   its corner, so the two read as one control. Position and width come from
+   the field's own box, measured by FilterPanelHost. */
+[data-interface-layout="mountain-view"] [data-mv-filter-panel] {
+  border-radius: var(--mv-search-radius);
+}
+
+/* The collapsed rail's hover peek. Only on desktop: below that breakpoint the
+   sidebar is already a drawer, opened by a tap rather than by a pointer that
+   does not exist. The width beats Tailwind's own `lg:w-full` on specificity,
+   which is what keeps the floating panel from filling the 72px column. */
+@media (min-width: 1024px) {
+  [data-interface-layout="mountain-view"] [data-mv-rail-peek] {
+    width: var(--mv-rail-peek-w);
+  }
+}
diff --git a/components/email/__tests__/mv-list-toolbar.test.tsx b/components/email/__tests__/mv-list-toolbar.test.tsx
new file mode 100644
index 000000000..0d9fd71ea
--- /dev/null
+++ b/components/email/__tests__/mv-list-toolbar.test.tsx
@@ -0,0 +1,158 @@
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import type { Email, Mailbox } from '@/lib/jmap/types';
+import { KEYWORD_PREFIX } from '@/lib/thread-utils';
+
+// "Move to" and "Labels" were reachable only from a row's context menu, so a
+// selection could be archived or deleted from the toolbar but not filed. Both
+// now sit in the batch half of the Mountain View list toolbar.
+
+const { MvListToolbar } = await import('../mv-list-toolbar');
+const { useEmailStore } = await import('@/stores/email-store');
+const { useAuthStore } = await import('@/stores/auth-store');
+const { useSettingsStore } = await import('@/stores/settings-store');
+
+const rights = {
+  mayReadItems: true, mayAddItems: true, mayRemoveItems: true, maySetSeen: true,
+  maySetKeywords: true, mayCreateChild: true, mayRename: true, mayDelete: true, maySubmit: true,
+};
+
+const mailbox = (id: string, name: string, role?: string): Mailbox =>
+  ({ id, name, role, sortOrder: 0, totalEmails: 0, unreadEmails: 0, totalThreads: 0,
+     unreadThreads: 0, isSubscribed: true, myRights: rights }) as Mailbox;
+
+const message = (id: string, keywords: Record<string, boolean> = {}): Email =>
+  ({ id, threadId: id, keywords, mailboxIds: { inbox: true } }) as unknown as Email;
+
+const mailboxes = [mailbox('inbox', 'Inbox', 'inbox'), mailbox('receipts', 'Receipts')];
+
+describe('MvListToolbar filing actions', () => {
+  const batchMoveToMailbox = vi.fn().mockResolvedValue(undefined);
+  const batchSetTag = vi.fn().mockResolvedValue(undefined);
+
+  beforeEach(() => {
+    batchMoveToMailbox.mockClear();
+    batchSetTag.mockClear();
+    const emails = [message('a', { [KEYWORD_PREFIX + 'work']: true }), message('b')];
+    useAuthStore.setState({ client: {} as never } as never);
+    useSettingsStore.setState({
+      emailKeywords: [{ id: 'work', label: 'Work', color: 'blue' }],
+      nestedTags: false,
+    } as never);
+    useEmailStore.setState({
+      emails,
+      mailboxes,
+      selectedMailbox: 'inbox',
+      selectedEmailIds: new Set(emails.map((email) => email.id)),
+      isUnifiedView: false,
+      unifiedRole: null,
+      batchMoveToMailbox,
+      batchSetTag,
+    } as never);
+  });
+
+  const toolbar = () =>
+    render(<MvListToolbar loadedCount={2} onRefresh={() => {}} />);
+
+  it('files the selection into a folder that will take it', async () => {
+    toolbar();
+
+    fireEvent.click(screen.getByLabelText('move_to'));
+    fireEvent.click(screen.getByText('Receipts'));
+
+    await waitFor(() => expect(batchMoveToMailbox).toHaveBeenCalledWith({}, 'receipts'));
+  });
+
+  it('does not offer the folder you are already in as a destination', () => {
+    toolbar();
+
+    fireEvent.click(screen.getByLabelText('move_to'));
+    expect(screen.queryByText('mailboxes.inbox')).toBeNull();
+  });
+
+  it('puts a tag on the whole selection when only some of it carries the tag', async () => {
+    toolbar();
+
+    fireEvent.click(screen.getByLabelText('tag'));
+    fireEvent.click(screen.getByText('Work'));
+
+    await waitFor(() => expect(batchSetTag).toHaveBeenCalledTimes(1));
+    expect(batchSetTag).toHaveBeenCalledWith({}, 'work', true);
+  });
+
+  it('takes a tag off once the whole selection carries it', async () => {
+    const emails = [
+      message('a', { [KEYWORD_PREFIX + 'work']: true }),
+      message('b', { [KEYWORD_PREFIX + 'work']: true }),
+    ];
+    useEmailStore.setState({
+      emails,
+      selectedEmailIds: new Set(emails.map((email) => email.id)),
+    } as never);
+    toolbar();
+
+    fireEvent.click(screen.getByLabelText('tag'));
+    fireEvent.click(screen.getByText('Work'));
+
+    await waitFor(() => expect(batchSetTag).toHaveBeenCalledTimes(1));
+    expect(batchSetTag).toHaveBeenCalledWith({}, 'work', false);
+  });
+
+  it('shows neither control until something is selected', () => {
+    useEmailStore.setState({ selectedEmailIds: new Set() } as never);
+    toolbar();
+
+    expect(screen.queryByLabelText('move_to')).toBeNull();
+    expect(screen.queryByLabelText('tag')).toBeNull();
+  });
+});
+
+describe('MvListToolbar overflow menu', () => {
+  beforeEach(() => {
+    useAuthStore.setState({ client: {} as never } as never);
+    useEmailStore.setState({
+      emails: [message('a')],
+      mailboxes,
+      selectedMailbox: 'inbox',
+      selectedEmailIds: new Set(),
+      isUnifiedView: false,
+      unifiedRole: null,
+    } as never);
+  });
+
+  const open = () => fireEvent.click(screen.getAllByLabelText('mark_folder_read')[0]);
+
+  it('offers marking every folder read, not just this one', () => {
+    render(
+      <MvListToolbar
+        loadedCount={1}
+        onRefresh={() => {}}
+        onMarkFolderRead={() => {}}
+        onMarkAllFoldersRead={() => {}}
+      />
+    );
+    open();
+
+    expect(screen.getByText('mark_all_folders_read')).toBeInTheDocument();
+  });
+
+  it('withholds emptying the folder outside spam and the bin', () => {
+    render(<MvListToolbar loadedCount={1} onRefresh={() => {}} onEmptyFolder={() => {}} />);
+    open();
+
+    expect(screen.queryByText('empty_folder')).toBeNull();
+  });
+
+  it('offers it in the bin', () => {
+    useEmailStore.setState({
+      mailboxes: [mailbox('trash', 'Trash', 'trash')],
+      selectedMailbox: 'trash',
+    } as never);
+    const onEmptyFolder = vi.fn();
+    render(<MvListToolbar loadedCount={1} onRefresh={() => {}} onEmptyFolder={onEmptyFolder} />);
+    open();
+
+    fireEvent.click(screen.getByText('empty_folder'));
+    expect(onEmptyFolder).toHaveBeenCalledOnce();
+  });
+});
diff --git a/components/email/__tests__/thread-list-item.test.tsx b/components/email/__tests__/thread-list-item.test.tsx
index ae627403d..17ec36186 100644
--- a/components/email/__tests__/thread-list-item.test.tsx
+++ b/components/email/__tests__/thread-list-item.test.tsx
@@ -1,8 +1,9 @@
-import { render, screen, act } from '@testing-library/react';
+import { render, screen, act, fireEvent } from '@testing-library/react';
 import { describe, it, expect, vi, beforeEach } from 'vitest';
 import { ThreadListItem } from '../thread-list-item';
 import { useSettingsStore, DEFAULT_KEYWORDS } from '@/stores/settings-store';
 import { useEmailStore } from '@/stores/email-store';
+import { useUIStore } from '@/stores/ui-store';
 import { groupEmailsByThread } from '@/lib/thread-utils';
 import type { Email } from '@/lib/jmap/types';
 
@@ -60,12 +61,17 @@ function renderRow(email: Email) {
   );
 }
 
+beforeEach(() => {
+  useUIStore.setState({ isMobile: false, isTablet: false, isDesktop: true });
+});
+
 describe('ThreadListItem tag badge', () => {
   beforeEach(() => {
     useSettingsStore.setState({
       emailKeywords: [...DEFAULT_KEYWORDS],
       showPreview: false,
       mailLayout: 'split',
+      interfaceLayout: 'default',
     });
     useEmailStore.setState({
       selectedEmailIds: new Set<string>(),
@@ -139,6 +145,7 @@ describe('ThreadListItem multi-message thread', () => {
       emailKeywords: [...DEFAULT_KEYWORDS],
       showPreview: false,
       mailLayout: 'split',
+      interfaceLayout: 'default',
     });
     useEmailStore.setState({
       selectedEmailIds: new Set<string>(),
@@ -200,6 +207,7 @@ describe('ThreadListItem row content', () => {
       emailKeywords: [...DEFAULT_KEYWORDS],
       showPreview: false,
       mailLayout: 'split',
+      interfaceLayout: 'default',
     });
     useEmailStore.setState({
       selectedEmailIds: new Set<string>(),
@@ -223,6 +231,51 @@ describe('ThreadListItem row content', () => {
     // rather than getting a paragraph of its own.
     expect(container.querySelector('p')).toBeNull();
   });
+
+  it('puts the star at the trailing edge in the Mountain View phone row', () => {
+    useSettingsStore.setState({ interfaceLayout: 'mountain-view', mailLayout: 'split' });
+    useUIStore.setState({ isMobile: true, isTablet: false, isDesktop: false });
+    const onToggleStar = vi.fn();
+    const [thread] = groupEmailsByThread([makeEmail()]);
+    const { container } = render(
+      <ThreadListItem
+        thread={thread}
+        isExpanded={false}
+        onToggleExpand={() => {}}
+        onEmailSelect={() => {}}
+        onToggleStar={onToggleStar}
+      />,
+    );
+
+    const star = container.querySelector<HTMLButtonElement>('[data-mv-mobile-row] button[aria-pressed]');
+    expect(star).not.toBeNull();
+    fireEvent.click(star!);
+
+    expect(onToggleStar).toHaveBeenCalledTimes(1);
+    expect(container.querySelector('[data-mv-mobile-row]')).toBeInTheDocument();
+  });
+});
+
+describe('ThreadListItem Mountain View phone row layout', () => {
+  it('sets the star at the end of the preview line, not under the time', () => {
+    useSettingsStore.setState({ interfaceLayout: 'mountain-view', mailLayout: 'split', showPreview: true, density: 'regular' } as never);
+    useUIStore.setState({ isMobile: true, isTablet: false, isDesktop: false });
+    const [thread] = groupEmailsByThread([makeEmail()]);
+    const { container } = render(
+      <ThreadListItem
+        thread={thread}
+        isExpanded={false}
+        onToggleExpand={() => {}}
+        onEmailSelect={() => {}}
+        onToggleStar={() => {}}
+      />,
+    );
+
+    const stars = container.querySelectorAll('[data-mv-mobile-row] button[aria-pressed]');
+    expect(stars).toHaveLength(1);
+    // Same line as the preview text: snippet ... star.
+    expect(stars[0].parentElement?.querySelector('p')).not.toBeNull();
+  });
 });
 
 describe('ThreadListItem shift-range avatar selection', () => {
@@ -231,6 +284,7 @@ describe('ThreadListItem shift-range avatar selection', () => {
       emailKeywords: [...DEFAULT_KEYWORDS],
       showPreview: false,
       mailLayout: 'split',
+      interfaceLayout: 'default',
     });
   });
 
@@ -268,6 +322,7 @@ describe('ThreadListItem row tint', () => {
       emailKeywords: [...DEFAULT_KEYWORDS],
       showPreview: false,
       mailLayout: 'split',
+      interfaceLayout: 'default',
       tintListRowsByTag: true,
     });
     useEmailStore.setState({
@@ -311,6 +366,7 @@ describe('ThreadListItem account row tint', () => {
       emailKeywords: [...DEFAULT_KEYWORDS],
       showPreview: false,
       mailLayout: 'split',
+      interfaceLayout: 'default',
       tintListRowsByTag: true,
       tintListRowsByAccount: false,
     });
diff --git a/components/email/email-list.tsx b/components/email/email-list.tsx
index 0701150fd..c4bb0080f 100644
--- a/components/email/email-list.tsx
+++ b/components/email/email-list.tsx
@@ -17,6 +17,7 @@ import { useEmailStore, ArchiveMailboxNotFoundError } from "@/stores/email-store
 import { useAuthStore } from "@/stores/auth-store";
 import { useAccountStore } from "@/stores/account-store";
 import { useSettingsStore } from "@/stores/settings-store";
+import { useEffectiveMailLayout } from "@/hooks/use-effective-mail-layout";
 import { useUIStore } from "@/stores/ui-store";
 import { useMessageListTabsStore } from "@/stores/message-list-tabs-store";
 import { groupEmailsByThread, sortThreadGroups, threadKeyFor, getEmailTagIds } from "@/lib/thread-utils";
@@ -62,6 +63,11 @@ interface EmailListProps {
   onLoadMoreScheduled?: () => void;
   onCancelScheduledForEdit?: (email: Email) => void | Promise<void>;
   onRescheduleScheduled?: (email: Email) => void | Promise<void>;
+  /**
+   * Mountain View folds the batch verbs into the single toolbar above the
+   * list, so the separate bar that would otherwise slide in here is redundant.
+   */
+  hideBatchToolbar?: boolean;
 }
 
 export function EmailList({
@@ -91,6 +97,7 @@ export function EmailList({
   onMoveToMailbox,
   onEditDraft,
   isScheduledView = false,
+  hideBatchToolbar = false,
   onLoadMoreScheduled,
   onCancelScheduledForEdit,
   onRescheduleScheduled,
@@ -259,7 +266,7 @@ export function EmailList({
   const density = useSettingsStore((state) => state.density);
   const showPreview = useSettingsStore((state) => state.showPreview);
   const showVerificationCodes = useSettingsStore((state) => state.showVerificationCodes);
-  const mailLayout = useSettingsStore((state) => state.mailLayout);
+  const mailLayout = useEffectiveMailLayout();
   const footerHasMore = hasMore ?? hasMoreEmails;
   const footerIsLoadingMore = isLoadingMoreItems ?? isLoadingMore;
   const isMobile = useUIStore((state) => state.isMobile);
@@ -529,7 +536,7 @@ export function EmailList({
         ref={batchToolbarRef}
         className={cn(
           "transition-all duration-300 ease-in-out overflow-hidden",
-          hasSelection && !isScheduledView ? "max-h-16 opacity-100" : "max-h-0 opacity-0"
+          hasSelection && !isScheduledView && !hideBatchToolbar ? "max-h-16 opacity-100" : "max-h-0 opacity-0"
         )}
       >
         <div className="px-4 py-2 border-b bg-accent/30 border-border flex items-center justify-between">
diff --git a/components/email/email-viewer.tsx b/components/email/email-viewer.tsx
index cdf91d2d0..a3430a995 100644
--- a/components/email/email-viewer.tsx
+++ b/components/email/email-viewer.tsx
@@ -14,7 +14,7 @@ import { buildContactsPath, buildMailPath } from "@/lib/deep-links";
 import { useCopyLink } from "@/hooks/use-copy-link";
 import { Button } from "@/components/ui/button";
 import { Avatar } from "@/components/ui/avatar";
-import { formatFileSize, cn, MailboxNode, formatDateTime, generateUUID } from "@/lib/utils";
+import { formatFileSize, cn, MailboxNode, formatDate, formatDateTime, generateUUID } from "@/lib/utils";
 import { buildMoveTargets, resolveMoveOwnerAccountId } from "@/lib/move-targets";
 import { emailDisplayDate } from "@/lib/email-date";
 import { TagBadge } from "./tag-badge";
@@ -89,6 +89,7 @@ import { useTranslations } from "next-intl";
 import { useRouter } from "@/i18n/navigation";
 import type { Attachment as PostalMimeAttachment } from 'postal-mime';
 import { useSettingsStore } from "@/stores/settings-store";
+import { useEffectiveMailLayout } from "@/hooks/use-effective-mail-layout";
 import { useUIStore } from "@/stores/ui-store";
 import { useContactStore, getContactDisplayName, getContactPrimaryEmail } from "@/stores/contact-store";
 import { toast } from "@/stores/toast-store";
@@ -705,8 +706,9 @@ export function EmailViewer({
   const emailKeywords = useSettingsStore((state) => state.emailKeywords);
   const { sortTagIds, tagColor } = useKeywordFormat();
   const toolbarPosition = useSettingsStore((state) => state.toolbarPosition);
-  const showToolbarLabels = useSettingsStore((state) => state.showToolbarLabels);
-  const mailLayout = useSettingsStore((state) => state.mailLayout);
+  const showToolbarLabelsSetting = useSettingsStore((state) => state.showToolbarLabels);
+  const interfaceLayout = useSettingsStore((state) => state.interfaceLayout);
+  const mailLayout = useEffectiveMailLayout();
   const calendarInvitationParsingEnabled = useSettingsStore((state) => state.calendarInvitationParsingEnabled);
   const readReceiptResponse = useSettingsStore((state) => state.readReceiptResponse);
   const hideInlineImageAttachments = useSettingsStore((state) => state.hideInlineImageAttachments);
@@ -758,6 +760,15 @@ export function EmailViewer({
 
   // Tablet list visibility
   const { isTablet, isMobile } = useDeviceDetection();
+  // Mountain View's conversation view: an icon-only toolbar at the top, and Reply /
+  // Reply all / Forward as buttons under the message rather than in the bar.
+  const mvViewer = interfaceLayout === 'mountain-view' && !isMobile;
+  // On the phone too Mountain View ends the message with Reply / Reply all / Forward
+  // and has no bar fixed at the bottom; previous / next move to the top bar.
+  const mvMobileViewer = interfaceLayout === 'mountain-view' && isMobile;
+  const mvReplyRow = mvViewer || mvMobileViewer;
+  // Mountain View's toolbars are icon-only, on the phone as on the desktop.
+  const showToolbarLabels = showToolbarLabelsSetting && interfaceLayout !== 'mountain-view';
   // Inside a Pro pane, `isMobile` above is pane-width based: overlays that
   // would go viewport-fixed must instead cover just the pane (via
   // PaneOverlay + absolute positioning), and viewport CSS breakpoints like
@@ -3040,6 +3051,32 @@ export function EmailViewer({
             <ChevronLeft className="w-5 h-5" />
           </Button>
         )}
+        {showBackButton && mvMobileViewer && (
+          <>
+            <Button
+              variant="ghost"
+              size="icon"
+              onClick={onNavigatePrev}
+              disabled={!onNavigatePrev}
+              className="h-9 w-9 flex-shrink-0"
+              aria-label={t('tooltips.previous')}
+              title={t('tooltips.previous')}
+            >
+              <ChevronUp className="w-5 h-5" />
+            </Button>
+            <Button
+              variant="ghost"
+              size="icon"
+              onClick={onNavigateNext}
+              disabled={!onNavigateNext}
+              className="h-9 w-9 flex-shrink-0"
+              aria-label={t('tooltips.next')}
+              title={t('tooltips.next')}
+            >
+              <ChevronDown className="w-5 h-5" />
+            </Button>
+          </>
+        )}
         {isScheduled && canCancelScheduled && (
           <>
             <Button
@@ -3084,7 +3121,7 @@ export function EmailViewer({
             <span className="text-sm">{t('edit_draft')}</span>
           </Button>
         )}
-        {!isScheduled && !isDraft && (<>
+        {!isScheduled && !isDraft && !mvViewer && (<>
         <Button
           variant="ghost"
           size="sm"
@@ -3362,7 +3399,7 @@ export function EmailViewer({
             onClick={() => { setMoreMenuOpen(!moreMenuOpen); setMoreMenuSlideEnabled(true); setMoreMenuSub(null); setTagMenuOpen(false); setMoveMenuOpen(false); }}
           >
             <MoreVertical className="w-4 h-4 text-muted-foreground" />
-            <span className="text-[10px] leading-tight sm:hidden">{t('more_actions')}</span>
+            {interfaceLayout !== 'mountain-view' && <span className="text-[10px] leading-tight sm:hidden">{t('more_actions')}</span>}
           </Button>
           {moreMenuOpen && !isMobile && (
             <div
@@ -3985,8 +4022,9 @@ export function EmailViewer({
                 </div>
               )}
             </div>
-            {/* Date/time on the right of subject row - hidden on mobile, shown next to sender */}
-            <div className="hidden sm:block flex-shrink-0 text-end">
+            {/* Date/time on the right of subject row - hidden on mobile, shown next to sender.
+                Mountain View puts it on the sender's row instead, and shows no size. */}
+            <div className={cn("hidden flex-shrink-0 text-end", !mvViewer && "sm:block")}>
               <span className="text-xs lg:text-sm text-muted-foreground whitespace-nowrap">
                 {formatDateTime(emailDisplayDate(email), timeFormat, { weekday: 'short', year: 'numeric', month: 'short', day: 'numeric' })}
               </span>
@@ -4012,7 +4050,7 @@ export function EmailViewer({
       )}
 
       {/* Email Content Area */}
-      <div className={cn("flex-1 overflow-auto overscroll-contain bg-muted/30", isMobile && "pb-[calc(3.25rem+env(safe-area-inset-bottom)/2)] sm:pb-0")}>
+      <div className={cn("flex-1 overflow-auto overscroll-contain bg-muted/30", isMobile && !mvMobileViewer && "pb-[calc(3.25rem+env(safe-area-inset-bottom)/2)] sm:pb-0")}>
       <div className="min-h-full flex flex-col">
 
       {/* === SENDER INFO (Desktop) === */}
@@ -4047,6 +4085,9 @@ export function EmailViewer({
                     ) : (
                       <span className="font-semibold text-foreground">{t('unknown_sender')}</span>
                     )}
+                    {mvViewer && sender?.email && sender?.name && (
+                      <span className="text-xs text-muted-foreground truncate">&lt;{sender.email}&gt;</span>
+                    )}
                     <EmailIdentityBadge email={email} identities={identities} />
                     {shouldShowUnsubBanner && listHeaders?.listUnsubscribe && (
                       <UnsubscribeBanner
@@ -4061,9 +4102,14 @@ export function EmailViewer({
                         }}
                       />
                     )}
+                    {mvViewer && (
+                      <span className="ms-auto ps-2 text-xs text-muted-foreground whitespace-nowrap" data-mv-sender-date="">
+                        {formatDateTime(emailDisplayDate(email), timeFormat, { weekday: 'short', year: 'numeric', month: 'short', day: 'numeric' })}
+                      </span>
+                    )}
                   </div>
-                  {/* Email address under name */}
-                  {sender?.email && sender?.name && (
+                  {/* Email address under name (on the name's line under Mountain View) */}
+                  {!mvViewer && sender?.email && sender?.name && (
                     <div className="text-sm text-muted-foreground mt-0.5 truncate">{sender.email}</div>
                   )}
                 </div>
@@ -4336,8 +4382,8 @@ export function EmailViewer({
                   />
                 )}
               </div>
-              {/* Email address under name */}
-              {sender?.email && sender?.name && (
+              {/* Email address under name - Mountain View keeps it in the details */}
+              {!mvMobileViewer && sender?.email && sender?.name && (
                 <div className="text-xs text-muted-foreground mt-0.5 truncate">{sender.email}</div>
               )}
               {/* Row 2: Recipients */}
@@ -4379,9 +4425,11 @@ export function EmailViewer({
             {/* Date/time + size on the right (mobile) */}
             <div className="sm:hidden flex-shrink-0 text-end ms-2">
               <span className="text-xs text-muted-foreground whitespace-nowrap">
-                {formatDateTime(emailDisplayDate(email), timeFormat, { weekday: 'short', year: 'numeric', month: 'short', day: 'numeric' })}
+                {mvMobileViewer
+                  ? formatDate(emailDisplayDate(email))
+                  : formatDateTime(emailDisplayDate(email), timeFormat, { weekday: 'short', year: 'numeric', month: 'short', day: 'numeric' })}
               </span>
-              {email.size > 0 && (
+              {email.size > 0 && !mvMobileViewer && (
                 <div className="text-xs text-muted-foreground/60">
                   {formatFileSize(email.size)}
                 </div>
@@ -5322,8 +5370,29 @@ export function EmailViewer({
 
           <PluginSlot name="email-footer" />
 
+          {/* Mountain View: Reply / Reply all / Forward as buttons under the message. */}
+          {mvReplyRow && !isDraft && !isScheduled && !isBodyLoading && (effectiveEmailContent.isHtml ? iframeReady : true) && (
+            <div
+              className={cn("pb-6 pt-2", isMobile ? "grid grid-cols-3 gap-2 px-4" : "flex flex-wrap items-center gap-2 px-6")}
+              data-mv-reply-row=""
+            >
+              <Button variant="outline" className={cn("h-9 rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={() => onReply?.()}>
+                <Reply className="w-4 h-4" />
+                {t('reply')}
+              </Button>
+              <Button variant="outline" className={cn("h-9 rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={onReplyAll}>
+                <ReplyAll className="w-4 h-4" />
+                {t('reply_all')}
+              </Button>
+              <Button variant="outline" className={cn("h-9 rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={onForward}>
+                <Forward className="w-4 h-4" />
+                {t('forward')}
+              </Button>
+            </div>
+          )}
+
           {/* Quick Reply Section - hidden for drafts and while loading a new email */}
-          {!isDraft && !isScheduled && !isBodyLoading && (effectiveEmailContent.isHtml ? iframeReady : true) && (<div className="bg-background border-t border-border px-6 mt-auto" style={{ paddingBlock: 'var(--density-header-py)' }}>
+          {!mvReplyRow && !isDraft && !isScheduled && !isBodyLoading && (effectiveEmailContent.isHtml ? iframeReady : true) && (<div className="bg-background border-t border-border px-6 mt-auto" style={{ paddingBlock: 'var(--density-header-py)' }}>
             <div className="flex items-start" style={{ gap: 'var(--density-item-gap)' }}>
               <div className="flex-shrink-0">
                 <Avatar
@@ -5470,7 +5539,7 @@ export function EmailViewer({
     {/* Mobile bottom action bar - pane-scoped inside a Pro pane (the
         viewport `sm:hidden` guard would otherwise hide it there, and
         `fixed` would span the whole app instead of the pane). */}
-    {isMobile && (
+    {isMobile && !mvMobileViewer && (
       <nav className={cn(
         "z-50 bg-background border-t border-border overflow-hidden pb-[calc(env(safe-area-inset-bottom)/2)]",
         isPaneScoped ? "absolute bottom-0 left-0 right-0" : "fixed bottom-0 left-0 right-0 sm:hidden",
diff --git a/components/email/mv-compose-window.tsx b/components/email/mv-compose-window.tsx
new file mode 100644
index 000000000..6febf5937
--- /dev/null
+++ b/components/email/mv-compose-window.tsx
@@ -0,0 +1,76 @@
+"use client";
+
+import { useState, type ReactNode } from "react";
+import { useTranslations } from "next-intl";
+import { Maximize2, Minimize2, Minus } from "@/components/icons";
+import { cn } from "@/lib/utils";
+
+type WindowState = "normal" | "minimized" | "maximized";
+
+/**
+ * Mountain View's compose window: a panel docked at the bottom-right corner
+ * over the mail list, which can be folded down to its title bar or opened up
+ * to a large centred dialog. The composer inside stays mounted throughout, so folding it
+ * keeps the draft exactly as it was.
+ */
+export function MvComposeWindow({ children }: { children: ReactNode }) {
+  const t = useTranslations("email_composer");
+  const [state, setState] = useState<WindowState>("normal");
+  const minimized = state === "minimized";
+  const maximized = state === "maximized";
+
+  return (
+    <>
+      {maximized && (
+        <div
+          className="fixed inset-0 z-40 bg-black/40"
+          aria-hidden
+          onClick={() => setState("normal")}
+        />
+      )}
+      <div
+        data-mv-compose-window=""
+        data-state={state}
+        className={cn(
+          "fixed z-40 flex flex-col overflow-hidden border border-border bg-background shadow-2xl",
+          maximized
+            ? "inset-x-[8vw] inset-y-[6vh] rounded-2xl"
+            : "bottom-0 end-6 w-[min(560px,calc(100vw-3rem))] rounded-t-2xl",
+          minimized && "h-14",
+          state === "normal" && "h-[min(640px,calc(100dvh-5rem))]",
+        )}
+      >
+        <div className="absolute top-2.5 end-3 z-10 flex items-center gap-0.5">
+          <button
+            type="button"
+            onClick={() => setState(minimized ? "normal" : "minimized")}
+            className="grid h-8 w-8 place-items-center rounded-full text-muted-foreground hover:bg-muted hover:text-foreground"
+            aria-label={minimized ? t("restore") : t("minimize")}
+            title={minimized ? t("restore") : t("minimize")}
+          >
+            <Minus className="h-4 w-4" />
+          </button>
+          <button
+            type="button"
+            onClick={() => setState(maximized ? "normal" : "maximized")}
+            className="grid h-8 w-8 place-items-center rounded-full text-muted-foreground hover:bg-muted hover:text-foreground"
+            aria-label={maximized ? t("restore") : t("maximize")}
+            title={maximized ? t("restore") : t("maximize")}
+          >
+            {maximized ? <Minimize2 className="h-4 w-4" /> : <Maximize2 className="h-4 w-4" />}
+          </button>
+        </div>
+        {/* Folded down, the title bar is the whole window and opens it again. */}
+        {minimized && (
+          <button
+            type="button"
+            className="absolute inset-0 end-24 z-[5]"
+            aria-label={t("restore")}
+            onClick={() => setState("normal")}
+          />
+        )}
+        <div className="flex min-h-0 flex-1 flex-col">{children}</div>
+      </div>
+    </>
+  );
+}
diff --git a/components/email/mv-list-toolbar.tsx b/components/email/mv-list-toolbar.tsx
new file mode 100644
index 000000000..3f320d975
--- /dev/null
+++ b/components/email/mv-list-toolbar.tsx
@@ -0,0 +1,529 @@
+"use client";
+
+import { useCallback, useEffect, useRef, useState } from "react";
+import {
+  Archive,
+  CheckSquare,
+  Folder,
+  FolderInput,
+  Loader2,
+  Mail,
+  MailOpen,
+  MoreVertical,
+  RotateCcw,
+  ShieldAlert,
+  ShieldCheck,
+  Square,
+  Tag,
+  Trash2,
+} from "@/components/icons";
+import { useTranslations } from "next-intl";
+import { useAuthStore } from "@/stores/auth-store";
+import { useEmailStore } from "@/stores/email-store";
+import { useConfirmDialog } from "@/hooks/use-confirm-dialog";
+import { useMenuNavigation } from "@/hooks/use-menu-navigation";
+import { ConfirmDialog } from "@/components/ui/confirm-dialog";
+import { TagPicker } from "@/components/email/tag-picker";
+import { localizeMailboxName } from "@/lib/mailbox-label";
+import { buildMoveTargets, resolveMoveOwnerAccountId } from "@/lib/move-targets";
+import { getEmailTagIds } from "@/lib/thread-utils";
+import { cn, type MailboxNode } from "@/lib/utils";
+
+interface MvListToolbarProps {
+  /** Loaded conversation count, for the right-hand range readout. */
+  loadedCount: number;
+  /** Total in the folder, when the server has told us. */
+  totalCount?: number;
+  onRefresh: () => void;
+  isRefreshing?: boolean;
+  onMarkFolderRead?: () => void;
+  onMarkAllFoldersRead?: () => void;
+  /** Only offered where emptying is the usual thing to do: spam and the bin. */
+  onEmptyFolder?: () => void;
+  /** Scheduled view: only the per-message scheduling actions make sense. */
+  disabled?: boolean;
+}
+
+function ToolbarButton({
+  icon: Icon,
+  label,
+  onClick,
+  disabled,
+  busy,
+  className,
+}: {
+  icon: typeof Archive;
+  label: string;
+  onClick: () => void;
+  disabled?: boolean;
+  busy?: boolean;
+  className?: string;
+}) {
+  return (
+    <button
+      type="button"
+      onClick={onClick}
+      disabled={disabled}
+      title={label}
+      aria-label={label}
+      className={cn(
+        "grid place-items-center w-10 h-10 rounded-full transition-colors shrink-0",
+        "text-muted-foreground hover:bg-foreground/10 hover:text-foreground",
+        disabled && "opacity-50 cursor-not-allowed hover:bg-transparent",
+        className
+      )}
+    >
+      {busy ? <Loader2 className="w-[18px] h-[18px] animate-spin" /> : <Icon className="w-[18px] h-[18px]" />}
+    </button>
+  );
+}
+
+/**
+ * Mountain View's single list toolbar: one row above the list that morphs.
+ * With nothing selected it offers select-all, refresh and an overflow menu;
+ * as soon as a conversation is ticked the batch verbs appear in the same row,
+ * rather than in a second bar that pushes the list down.
+ */
+export function MvListToolbar({
+  loadedCount,
+  totalCount,
+  onRefresh,
+  isRefreshing = false,
+  onMarkFolderRead,
+  onMarkAllFoldersRead,
+  onEmptyFolder,
+  disabled = false,
+}: MvListToolbarProps) {
+  const t = useTranslations("email_list");
+  const tBatch = useTranslations("email_list.batch_actions");
+  const tActions = useTranslations("settings.email_behavior.hover_actions");
+  const tFolder = useTranslations("mailbox_context_menu");
+  const tMenu = useTranslations("context_menu");
+  const tSidebar = useTranslations("sidebar");
+
+  const client = useAuthStore((s) => s.client);
+  const {
+    emails,
+    mailboxes,
+    selectedMailbox,
+    selectedEmailIds,
+    selectAllEmails,
+    clearSelection,
+    batchArchive,
+    batchDelete,
+    batchMarkAsRead,
+    batchMarkAsSpam,
+    batchUndoSpam,
+    batchMoveToMailbox,
+    batchSetTag,
+    isUnifiedView,
+    unifiedRole,
+  } = useEmailStore();
+
+  const [isProcessing, setIsProcessing] = useState(false);
+  const [menuOpen, setMenuOpen] = useState(false);
+  const menuButtonRef = useRef<HTMLButtonElement>(null);
+  const closeMenu = useCallback(() => setMenuOpen(false), []);
+  const { menuRef, onKeyDown: onMenuKeyDown } = useMenuNavigation<HTMLDivElement>({
+    open: menuOpen,
+    onClose: closeMenu,
+    triggerRef: menuButtonRef,
+  });
+  const [moveOpen, setMoveOpen] = useState(false);
+  const moveButtonRef = useRef<HTMLButtonElement>(null);
+  const closeMove = useCallback(() => setMoveOpen(false), []);
+  const { menuRef: moveRef, onKeyDown: onMoveKeyDown } = useMenuNavigation<HTMLDivElement>({
+    open: moveOpen,
+    onClose: closeMove,
+    triggerRef: moveButtonRef,
+  });
+
+  const [tagOpen, setTagOpen] = useState(false);
+  const tagButtonRef = useRef<HTMLButtonElement>(null);
+  const closeTag = useCallback(() => setTagOpen(false), []);
+  const { menuRef: tagRef, onKeyDown: onTagKeyDown } = useMenuNavigation<HTMLDivElement>({
+    open: tagOpen,
+    onClose: closeTag,
+    triggerRef: tagButtonRef,
+  });
+
+  const { dialogProps: confirmDialogProps, confirm: confirmDialog } = useConfirmDialog();
+
+  useEffect(() => {
+    if (!menuOpen) return;
+    const onPointerDown = (e: MouseEvent) => {
+      if (
+        menuButtonRef.current?.contains(e.target as Node) ||
+        menuRef.current?.contains(e.target as Node)
+      ) return;
+      setMenuOpen(false);
+    };
+    document.addEventListener("mousedown", onPointerDown);
+    return () => document.removeEventListener("mousedown", onPointerDown);
+  }, [menuOpen, menuRef]);
+
+  useEffect(() => {
+    if (!moveOpen && !tagOpen) return;
+    const onPointerDown = (e: MouseEvent) => {
+      const inside = (button: HTMLElement | null, menu: HTMLElement | null) =>
+        button?.contains(e.target as Node) || menu?.contains(e.target as Node);
+      if (!inside(moveButtonRef.current, moveRef.current)) setMoveOpen(false);
+      if (!inside(tagButtonRef.current, tagRef.current)) setTagOpen(false);
+    };
+    document.addEventListener("mousedown", onPointerDown);
+    return () => document.removeEventListener("mousedown", onPointerDown);
+  }, [moveOpen, tagOpen, moveRef, tagRef]);
+
+  const selectionCount = selectedEmailIds.size;
+  const hasSelection = selectionCount > 0;
+  const allSelected = hasSelection && selectionCount === emails.length;
+  // Optimistic updates and demo fixtures can briefly leave the server total
+  // behind the rows already loaded. Never render an impossible "23 of 22".
+  const displayedTotal = Math.max(totalCount ?? loadedCount, loadedCount);
+
+  const currentRole = mailboxes.find((mb) => mb.id === selectedMailbox)?.role
+    ?? (isUnifiedView ? (unifiedRole ?? undefined) : undefined);
+  const isInJunk = currentRole === "junk";
+  const isInTrash = currentRole === "trash";
+  // Marking your own drafts or sent mail as spam is meaningless.
+  const spamApplicable = !["sent", "drafts", "scheduled"].includes(currentRole ?? "");
+
+  const run = async (action: () => Promise<void>) => {
+    if (!client || isProcessing) return;
+    setIsProcessing(true);
+    try {
+      await action();
+    } finally {
+      setTimeout(() => setIsProcessing(false), 400);
+    }
+  };
+
+  const handleSelectAllToggle = () => {
+    if (disabled) return;
+    if (hasSelection) {
+      if (allSelected) clearSelection();
+      else selectAllEmails();
+      return;
+    }
+    if (emails.length > 0) selectAllEmails();
+  };
+
+  const handleDelete = () =>
+    run(async () => {
+      if (!client) return;
+      const confirmed = await confirmDialog({
+        title: isInTrash ? t("permanent_delete_confirm_title") : tBatch("delete_confirm_title"),
+        message: isInTrash
+          ? t("permanent_delete_confirm_batch_message", { count: selectionCount })
+          : tBatch("delete_confirm_message", { count: selectionCount }),
+        confirmText: isInTrash ? t("permanent_delete") : tBatch("delete"),
+        variant: "destructive",
+      });
+      if (!confirmed) return;
+      await batchDelete(client, isInTrash);
+    });
+
+  const selectedEmails = emails.filter((email) => selectedEmailIds.has(email.id));
+
+  // The same targets the row's own context menu offers, with the account of
+  // the selection leading (#1149).
+  const { tree: moveTree, targetIds: moveTargetIds } = buildMoveTargets(mailboxes, {
+    currentMailboxId: selectedMailbox,
+    ownerAccountId: resolveMoveOwnerAccountId(selectedEmails[0], mailboxes, selectedMailbox),
+  });
+
+  const renderMoveNodes = (nodes: MailboxNode[], depth = 0): React.ReactNode =>
+    nodes.map((node) => {
+      const label = localizeMailboxName(node.role, node.name, (key) => tSidebar(`mailboxes.${key}`));
+      const isTarget = moveTargetIds.has(node.id);
+      return (
+        <div key={node.id}>
+          {isTarget ? (
+            <button
+              type="button"
+              role="menuitem"
+              onClick={() => handleMove(node.id)}
+              style={{ paddingInlineStart: `${12 + depth * 16}px` }}
+              className="w-full flex items-center gap-2 pe-3 py-2 text-start text-sm hover:bg-muted"
+            >
+              <Folder className="w-4 h-4 flex-shrink-0 text-muted-foreground" />
+              <span className="truncate">{label}</span>
+            </button>
+          ) : (
+            <div
+              style={{ paddingInlineStart: `${12 + depth * 16}px` }}
+              className="flex items-center gap-2 pe-3 py-2 text-sm text-muted-foreground"
+            >
+              <Folder className="w-4 h-4 flex-shrink-0" />
+              <span className="truncate">{label}</span>
+            </div>
+          )}
+          {node.children.length > 0 && renderMoveNodes(node.children, depth + 1)}
+        </div>
+      );
+    });
+
+  // What the tag picker shows: a tag every selected message carries is
+  // checked, one only some of them carry is drawn as partial.
+  const tagCounts = new Map<string, number>();
+  for (const email of selectedEmails) {
+    for (const tagId of getEmailTagIds(email.keywords)) tagCounts.set(tagId, (tagCounts.get(tagId) ?? 0) + 1);
+  }
+  const appliedTags: string[] = [];
+  const partialTags: string[] = [];
+  for (const [tagId, count] of tagCounts) (count === selectedEmails.length ? appliedTags : partialTags).push(tagId);
+
+  const handleMove = (mailboxId: string) => {
+    setMoveOpen(false);
+    void run(async () => {
+      if (client) await batchMoveToMailbox(client, mailboxId);
+    });
+  };
+
+  // A tag the whole selection carries comes off; any other goes onto all of
+  // it, as in the default toolbar.
+  const handleToggleTag = (tagId: string) => {
+    const add = !appliedTags.includes(tagId);
+    void run(async () => {
+      if (client) await batchSetTag(client, tagId, add);
+    });
+  };
+
+  const handleSpam = () =>
+    run(async () => {
+      if (!client) return;
+      const ids = Array.from(selectedEmailIds);
+      if (isInJunk) await batchUndoSpam(client, ids);
+      else await batchMarkAsSpam(client, ids);
+    });
+
+  return (
+    <div className="flex items-center gap-1 h-12 px-2 shrink-0">
+      <button
+        type="button"
+        role="checkbox"
+        aria-checked={allSelected ? true : hasSelection ? "mixed" : false}
+        onClick={handleSelectAllToggle}
+        disabled={disabled}
+        title={
+          hasSelection
+            ? allSelected
+              ? tBatch("clear_selection")
+              : tBatch("select_all")
+            : tBatch("select")
+        }
+        className={cn(
+          "grid place-items-center w-10 h-10 rounded-full transition-colors shrink-0",
+          "text-muted-foreground hover:bg-foreground/10 hover:text-foreground",
+          hasSelection && "text-primary",
+          disabled && "opacity-50 cursor-not-allowed hover:bg-transparent"
+        )}
+      >
+        {hasSelection ? (
+          <CheckSquare className="w-[18px] h-[18px]" />
+        ) : (
+          <Square className="w-[18px] h-[18px]" />
+        )}
+      </button>
+
+      <ToolbarButton
+        icon={RotateCcw}
+        label={t("loading")}
+        onClick={onRefresh}
+        disabled={!client || isRefreshing}
+        busy={isRefreshing}
+      />
+
+      <div className="relative shrink-0">
+        <button
+          ref={menuButtonRef}
+          type="button"
+          onClick={() => setMenuOpen((v) => !v)}
+          aria-haspopup="menu"
+          aria-expanded={menuOpen}
+          title={tFolder("mark_folder_read")}
+          aria-label={tFolder("mark_folder_read")}
+          className={cn(
+            "grid place-items-center w-10 h-10 rounded-full transition-colors",
+            menuOpen
+              ? "bg-foreground/10 text-foreground"
+              : "text-muted-foreground hover:bg-foreground/10 hover:text-foreground"
+          )}
+        >
+          <MoreVertical className="w-[18px] h-[18px]" />
+        </button>
+        {menuOpen && (
+          <div
+            ref={menuRef}
+            onKeyDown={onMenuKeyDown}
+            role="menu"
+            className="absolute start-0 top-full mt-1 z-50 min-w-56 rounded-lg border border-border bg-popover py-1 shadow-xl"
+          >
+            <button
+              type="button"
+              role="menuitem"
+              disabled={!onMarkFolderRead}
+              onClick={() => {
+                setMenuOpen(false);
+                onMarkFolderRead?.();
+              }}
+              className="w-full px-3 py-2 text-start text-sm hover:bg-muted disabled:opacity-50"
+            >
+              {tFolder("mark_folder_read")}
+            </button>
+            {onMarkAllFoldersRead && (
+              <button
+                type="button"
+                role="menuitem"
+                onClick={() => {
+                  setMenuOpen(false);
+                  onMarkAllFoldersRead();
+                }}
+                className="w-full px-3 py-2 text-start text-sm hover:bg-muted"
+              >
+                {tFolder("mark_all_folders_read")}
+              </button>
+            )}
+            {/* Offered only where emptying a folder is the usual thing to
+                do: spam and the bin. */}
+            {onEmptyFolder && (isInJunk || isInTrash) && (
+              <>
+                <div className="my-1 h-px bg-border" />
+                <button
+                  type="button"
+                  role="menuitem"
+                  onClick={() => {
+                    setMenuOpen(false);
+                    onEmptyFolder();
+                  }}
+                  className="w-full px-3 py-2 text-start text-sm text-destructive hover:bg-muted"
+                >
+                  {tFolder("empty_folder")}
+                </button>
+              </>
+            )}
+          </div>
+        )}
+      </div>
+
+      {hasSelection && !disabled && (
+        <>
+          <div className="w-px h-6 bg-border mx-1 shrink-0" />
+          <ToolbarButton
+            icon={Archive}
+            label={tActions("archive")}
+            onClick={() => run(async () => { if (client) await batchArchive(client); })}
+            disabled={isProcessing}
+            busy={isProcessing}
+          />
+          {spamApplicable && (
+            <ToolbarButton
+              icon={isInJunk ? ShieldCheck : ShieldAlert}
+              label={isInJunk ? tActions("not_spam") : tActions("spam")}
+              onClick={handleSpam}
+              disabled={isProcessing}
+            />
+          )}
+          <ToolbarButton
+            icon={Trash2}
+            label={tBatch("delete")}
+            onClick={handleDelete}
+            disabled={isProcessing}
+            className="hover:text-red-600 dark:hover:text-red-400"
+          />
+          <div className="w-px h-6 bg-border mx-1 shrink-0" />
+          {moveTree.length > 0 && (
+            <div className="relative shrink-0">
+              <button
+                ref={moveButtonRef}
+                type="button"
+                onClick={() => { setTagOpen(false); setMoveOpen((v) => !v); }}
+                aria-haspopup="menu"
+                aria-expanded={moveOpen}
+                title={tMenu("move_to")}
+                aria-label={tMenu("move_to")}
+                className={cn(
+                  "grid place-items-center w-10 h-10 rounded-full transition-colors",
+                  moveOpen
+                    ? "bg-foreground/10 text-foreground"
+                    : "text-muted-foreground hover:bg-foreground/10 hover:text-foreground"
+                )}
+              >
+                <FolderInput className="w-[18px] h-[18px]" />
+              </button>
+              {moveOpen && (
+                <div
+                  ref={moveRef}
+                  onKeyDown={onMoveKeyDown}
+                  role="menu"
+                  aria-label={tMenu("move_to")}
+                  className="absolute start-0 top-full mt-1 z-50 min-w-64 max-h-80 overflow-y-auto rounded-lg border border-border bg-popover py-1 shadow-xl"
+                >
+                  {renderMoveNodes(moveTree)}
+                </div>
+              )}
+            </div>
+          )}
+          <div className="relative shrink-0">
+            <button
+              ref={tagButtonRef}
+              type="button"
+              onClick={() => { setMoveOpen(false); setTagOpen((v) => !v); }}
+              aria-haspopup="menu"
+              aria-expanded={tagOpen}
+              title={tMenu("tag")}
+              aria-label={tMenu("tag")}
+              className={cn(
+                "grid place-items-center w-10 h-10 rounded-full transition-colors",
+                tagOpen
+                  ? "bg-foreground/10 text-foreground"
+                  : "text-muted-foreground hover:bg-foreground/10 hover:text-foreground"
+              )}
+            >
+              <Tag className="w-[18px] h-[18px]" />
+            </button>
+            {tagOpen && (
+              <div
+                ref={tagRef}
+                onKeyDown={onTagKeyDown}
+                role="menu"
+                aria-label={tMenu("tag")}
+                className="absolute start-0 top-full mt-1 z-50 min-w-64 rounded-lg border border-border bg-popover py-1 shadow-xl"
+              >
+                <TagPicker selectedIds={appliedTags} partialIds={partialTags} onToggle={handleToggleTag} />
+              </div>
+            )}
+          </div>
+          <div className="w-px h-6 bg-border mx-1 shrink-0" />
+          <ToolbarButton
+            icon={MailOpen}
+            label={tBatch("mark_read")}
+            onClick={() => run(async () => { if (client) await batchMarkAsRead(client, true); })}
+            disabled={isProcessing}
+          />
+          <ToolbarButton
+            icon={Mail}
+            label={tBatch("mark_unread")}
+            onClick={() => run(async () => { if (client) await batchMarkAsRead(client, false); })}
+            disabled={isProcessing}
+          />
+          <span className="ms-2 text-sm text-muted-foreground truncate">
+            {tBatch("selected_messages", { count: selectionCount })}
+          </span>
+        </>
+      )}
+
+      <div className="flex-1 min-w-0" />
+
+      {loadedCount > 0 && (
+        <span className="text-xs text-muted-foreground tabular-nums pe-2 shrink-0">
+          {/* The range readout. The list grows as it scrolls rather than
+              paging, so there are no previous/next arrows to go with it. */}
+          {t("conversations_range", { from: 1, to: loadedCount, total: displayedTotal })}
+        </span>
+      )}
+
+      <ConfirmDialog {...confirmDialogProps} />
+    </div>
+  );
+}
diff --git a/components/email/thread-list-item.tsx b/components/email/thread-list-item.tsx
index f8b7ea24c..96a0545a1 100644
--- a/components/email/thread-list-item.tsx
+++ b/components/email/thread-list-item.tsx
@@ -12,6 +12,7 @@ import { SelectableAvatar } from "@/components/email/selectable-avatar";
 import { Paperclip, Star, Pin, Circle, ChevronRight, ChevronDown, Loader2, MessageSquare, CheckSquare, Square, Reply, Forward, CalendarClock, Folder, Archive, Trash2, MailOpen, ShieldAlert } from "@/components/icons";
 import type { AppIcon } from "@/components/icons";
 import { useSettingsStore, KEYWORD_PALETTE } from "@/stores/settings-store";
+import { useEffectiveMailLayout } from "@/hooks/use-effective-mail-layout";
 import { accountTintKey, generateAvatarColor } from "@/lib/account-utils";
 import { useUIStore } from "@/stores/ui-store";
 import { useEmailStore } from "@/stores/email-store";
@@ -66,6 +67,101 @@ function RowChips({ email, loadAttachments, onOpenAttachment }: {
   return leading ? <div className="mt-1.5 flex">{leading}</div> : null;
 }
 
+/**
+ * Mountain View's leading controls: a checkbox and a star, both always
+ * visible and both acting on the row without opening it. They take the slot
+ * the default layout gives to the sender avatar.
+ */
+function MvRowLead({
+  checked,
+  onToggleChecked,
+  starred,
+  onToggleStar,
+  selectLabel,
+  starLabel,
+}: {
+  checked: boolean;
+  onToggleChecked: (e: React.MouseEvent) => void;
+  starred: boolean;
+  onToggleStar?: () => void;
+  selectLabel: string;
+  starLabel: string;
+}) {
+  return (
+    <div className="flex items-center gap-0.5 flex-shrink-0 self-center">
+      <button
+        type="button"
+        role="checkbox"
+        aria-checked={checked}
+        aria-label={selectLabel}
+        onClick={onToggleChecked}
+        className={cn(
+          "p-1 rounded-full transition-colors hover:bg-foreground/10",
+          checked && "text-primary"
+        )}
+      >
+        {checked ? (
+          <CheckSquare className="w-[18px] h-[18px]" />
+        ) : (
+          <Square className="w-[18px] h-[18px] text-muted-foreground" />
+        )}
+      </button>
+      {onToggleStar && (
+        <button
+          type="button"
+          aria-label={starLabel}
+          aria-pressed={starred}
+          title={starLabel}
+          onClick={(e) => {
+            e.stopPropagation();
+            onToggleStar();
+          }}
+          className="p-1 rounded-full transition-colors hover:bg-foreground/10"
+        >
+          <Star
+            className={cn(
+              "w-[18px] h-[18px]",
+              starred ? "fill-amber-400 text-amber-400" : "text-muted-foreground/60"
+            )}
+          />
+        </button>
+      )}
+    </div>
+  );
+}
+
+function MvMobileStar({
+  starred,
+  onToggle,
+  label,
+}: {
+  starred: boolean;
+  onToggle?: () => void;
+  label: string;
+}) {
+  return (
+    <button
+      type="button"
+      aria-label={label}
+      aria-pressed={starred}
+      title={label}
+      disabled={!onToggle}
+      onClick={(event) => {
+        event.stopPropagation();
+        onToggle?.();
+      }}
+      className="grid h-8 w-8 place-items-center rounded-full text-muted-foreground transition-colors hover:bg-foreground/10 disabled:pointer-events-none"
+    >
+      <Star
+        className={cn(
+          "h-[18px] w-[18px]",
+          starred ? "fill-amber-400 text-amber-400" : "text-muted-foreground/70"
+        )}
+      />
+    </button>
+  );
+}
+
 function StatusIcon({ icon: Icon, label, className }: { icon: AppIcon; label: string; className: string }) {
   return (
     <>
@@ -178,6 +274,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
   function SingleEmailItem({ email, selected, onClick, onDoubleClick, onContextMenu, showPreview, rowTint, onToggleStar, onMarkAsRead, onDelete, onArchive, onSetTag, onMarkAsSpam, onUndoSpam, onOpenAttachment, loadAttachments }, ref) {
     const t = useTranslations('email_viewer');
     const tBatch = useTranslations('email_list.batch_actions');
+    const tHover = useTranslations('settings.email_behavior.hover_actions');
     const tStatus = useTranslations('email_list');
     const isUnread = !email.keywords?.$seen;
     const isStarred = email.keywords?.$flagged;
@@ -198,9 +295,10 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
     const tintListRowsByTag = useSettingsStore((state) => state.tintListRowsByTag);
     const tintListRowsByAccount = useSettingsStore((state) => state.tintListRowsByAccount);
     const density = useSettingsStore((state) => state.density);
-    const mailLayout = useSettingsStore((state) => state.mailLayout);
+    const mailLayout = useEffectiveMailLayout();
     const timeFormat = useSettingsStore((state) => state.timeFormat);
     const showAvatarsInJunk = useSettingsStore((state) => state.showAvatarsInJunk);
+    const interfaceLayout = useSettingsStore((state) => state.interfaceLayout);
     const hideJunkAvatarImages = currentMailboxRole === 'junk' && !showAvatarsInJunk;
     // Show the originating folder in the aggregate "All …" views.
     const showSourceFolder = isUnifiedView && !!email.sourceFolder;
@@ -212,6 +310,12 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
     const isMobile = useUIStore((state) => state.isMobile);
     // The horizontal one-line "focus" layout doesn't fit on narrow screens; fall back to multi-line on mobile.
     const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
+    // Mountain View leads its rows with a checkbox and a clickable star
+    // instead of an avatar, and marks unread with weight alone. Only the
+    // one-line layout is shaped that way, so the two conditions travel
+    // together.
+    const mvRow = interfaceLayout === 'mountain-view' && isFocusedMailLayout;
+    const mvMobileRow = interfaceLayout === 'mountain-view' && isMobile;
     const trimmedPreview = cleanPreview(email.preview);
     const inlinePreview = showPreview && trimmedPreview ? ` ${trimmedPreview}` : '';
     // Search hits carry server snippets with the matched terms marked; they
@@ -337,19 +441,23 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
         data-subject={email.subject || ''}
         data-unread={isUnread ? 'true' : 'false'}
         data-starred={email.keywords?.$flagged ? 'true' : 'false'}
+        data-mv-mobile-row={mvMobileRow ? "" : undefined}
         aria-current={selected ? 'true' : undefined}
         className={cn(
           "relative group cursor-pointer select-none transition-shadow duration-200 border-b border-border overflow-hidden",
+          mvMobileRow && "border-b-transparent",
           resolvedRowTint ? resolvedRowTint : (
             selected
               ? "bg-accent"
-              : "bg-background"
+              : mvRow && !isUnread
+                ? "bg-muted/60"
+                : "bg-background"
           ),
           selected && !resolvedRowTint && "shadow-sm",
           !resolvedRowTint && !selected && !isChecked && "hover:bg-muted hover:shadow-sm",
           !resolvedRowTint && (selected || isChecked) && "hover:bg-accent hover:shadow-sm",
           resolvedRowTint && "hover:brightness-95 dark:hover:brightness-110",
-          isUnread && !resolvedRowTint && "bg-accent/30",
+          isUnread && !resolvedRowTint && !mvRow && !mvMobileRow && "bg-accent/30",
           isChecked && "ring-2 ring-primary/20",
           isChecked && !resolvedRowTint && "bg-accent/40",
           isDragging && "opacity-50 scale-[0.98] ring-2 ring-primary/30",
@@ -384,7 +492,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
           style={{ gap: 'var(--density-item-gap)', paddingBlock: 'var(--density-item-py)', transform: swipeEnabled && offsetX ? `translateX(${offsetX}px)` : undefined, transition: swipeEnabled && offsetX === 0 ? 'transform 200ms ease-out' : undefined }}
         >
           {/* Checkbox - only for extra-compact density (no avatar) while in selection mode */}
-          {density === 'extra-compact' && selectedEmailIds.size > 0 && (
+          {!mvRow && density === 'extra-compact' && selectedEmailIds.size > 0 && (
             <button
               onClick={handleCheckboxClick}
               role="checkbox"
@@ -407,7 +515,18 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
             </button>
           )}
 
-          {density !== 'extra-compact' && (
+          {mvRow && (
+            <MvRowLead
+              checked={isChecked}
+              onToggleChecked={handleCheckboxClick}
+              starred={!!isStarred}
+              onToggleStar={onToggleStar}
+              selectLabel={tBatch('select')}
+              starLabel={tHover('star')}
+            />
+          )}
+
+          {!mvRow && density !== 'extra-compact' && (
             <div className="relative flex flex-shrink-0 self-center">
               <SelectableAvatar
                 name={sender?.name}
@@ -423,12 +542,13 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
             </div>
           )}
 
-          {isUnread && density === 'extra-compact' && (
+          {isUnread && !mvRow && density === 'extra-compact' && (
             <UnreadDot besideAvatar={false} />
           )}
 
           <div className="flex-1 min-w-0">
             {isFocusedMailLayout ? (
+              <>
               <div className="flex items-center justify-between gap-3">
                 <div className="flex min-w-0 flex-1 items-center gap-3">
                   {isUnifiedView && email.accountId && accountColor && !tintListRowsByAccount && (
@@ -469,7 +589,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
                 </div>
                 <div className="flex items-center gap-2.5 shrink-0">
                   {isPinned && <StatusIcon icon={Pin} label={tStatus('pinned')} className="w-3.5 h-3.5 text-primary" />}
-                  {isStarred && <StatusIcon icon={Star} label={tStatus('starred')} className="w-3.5 h-3.5 fill-amber-400 text-amber-400" />}
+                  {isStarred && !mvRow && <StatusIcon icon={Star} label={tStatus('starred')} className="w-3.5 h-3.5 fill-amber-400 text-amber-400" />}
                   {isAnswered && !isForwarded && <StatusIcon icon={Reply} label={tStatus('replied')} className="w-3.5 h-3.5 text-muted-foreground" />}
                   {isForwarded && !isAnswered && <StatusIcon icon={Forward} label={tStatus('forwarded')} className="w-3.5 h-3.5 text-muted-foreground" />}
                   {isAnswered && isForwarded && (
@@ -498,6 +618,10 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
                   )}
                 </div>
               </div>
+              {mvRow && (
+                <RowChips email={email} loadAttachments={loadAttachments} onOpenAttachment={onOpenAttachment} />
+              )}
+              </>
             ) : (
               <>
                 <div className="flex items-center justify-between gap-2 mb-1">
@@ -530,7 +654,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
                       {isPinned && (
                         <StatusIcon icon={Pin} label={tStatus('pinned')} className="w-3.5 h-3.5 text-primary" />
                       )}
-                      {isStarred && (
+                      {isStarred && !mvMobileRow && (
                         <StatusIcon icon={Star} label={tStatus('starred')} className="w-3.5 h-3.5 fill-amber-400 text-amber-400" />
                       )}
                       {isAnswered && !isForwarded && (
@@ -570,6 +694,13 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
                         {formatDate(email.receivedAt)}
                       </span>
                     )}
+                    {mvMobileRow && !(showPreview && density !== 'extra-compact' && density !== 'compact') && (
+                      <MvMobileStar
+                        starred={!!isStarred}
+                        onToggle={onToggleStar}
+                        label={tHover('star')}
+                      />
+                    )}
                   </div>
                 </div>
 
@@ -592,14 +723,24 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
                 </div>
 
                 {showPreview && density !== 'extra-compact' && density !== 'compact' && (
-                  <p className={cn(
-                    "text-sm leading-relaxed line-clamp-2",
-                    isUnread
-                      ? "text-muted-foreground"
-                      : "text-muted-foreground/80"
-                  )}>
-                    {previewSnippet ? <SearchSnippetText snippet={previewSnippet} /> : (trimmedPreview || t('no_preview_available'))}
-                  </p>
+                  <div className={cn("flex min-w-0 items-center gap-1", !mvMobileRow && "contents")}>
+                    <p className={cn(
+                      "text-sm leading-relaxed",
+                      mvMobileRow ? "line-clamp-1 min-w-0 flex-1" : "line-clamp-2",
+                      isUnread
+                        ? "text-muted-foreground"
+                        : "text-muted-foreground/80"
+                    )}>
+                      {previewSnippet ? <SearchSnippetText snippet={previewSnippet} /> : (trimmedPreview || t('no_preview_available'))}
+                    </p>
+                    {mvMobileRow && (
+                      <MvMobileStar
+                        starred={!!isStarred}
+                        onToggle={onToggleStar}
+                        label={tHover('star')}
+                      />
+                    )}
+                  </div>
                 )}
                 <RowChips email={email} loadAttachments={loadAttachments} onOpenAttachment={onOpenAttachment} />
               </>
@@ -654,16 +795,24 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
     const t = useTranslations('threads');
     const tEmailViewer = useTranslations('email_viewer');
     const tBatch = useTranslations('email_list.batch_actions');
+    const tHover = useTranslations('settings.email_behavior.hover_actions');
     const tStatus = useTranslations('email_list');
     const showPreview = useSettingsStore((state) => state.showPreview);
     const density = useSettingsStore((state) => state.density);
-    const mailLayout = useSettingsStore((state) => state.mailLayout);
+    const mailLayout = useEffectiveMailLayout();
     const timeFormat = useSettingsStore((state) => state.timeFormat);
     const showAvatarsInJunk = useSettingsStore((state) => state.showAvatarsInJunk);
+    const interfaceLayout = useSettingsStore((state) => state.interfaceLayout);
     const isMobile = useUIStore((state) => state.isMobile);
     const { latestEmail, participantNames, hasUnread, hasStarred, hasPinned, hasAttachment, hasAnswered, hasForwarded, emailCount } = thread;
     // The horizontal one-line "focus" layout doesn't fit on narrow screens; fall back to multi-line on mobile.
     const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
+    // Mountain View leads its rows with a checkbox and a clickable star
+    // instead of an avatar, and marks unread with weight alone. Only the
+    // one-line layout is shaped that way, so the two conditions travel
+    // together.
+    const mvRow = interfaceLayout === 'mountain-view' && isFocusedMailLayout;
+    const mvMobileRow = interfaceLayout === 'mountain-view' && isMobile;
     const trimmedPreview = cleanPreview(latestEmail.preview);
     const inlinePreview = showPreview && trimmedPreview ? ` ${trimmedPreview}` : '';
     // In a search the matched mail need not be the thread's latest one: show
@@ -817,23 +966,31 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
     };
 
     return (
-      <div ref={ref} className={cn("border-b border-border", isThreadDragging && "opacity-50 scale-[0.98] ring-2 ring-primary/30")}>
+      <div ref={ref} className={cn(
+        "border-b border-border",
+        mvMobileRow && "border-b-transparent",
+        isThreadDragging && "opacity-50 scale-[0.98] ring-2 ring-primary/30"
+      )}>
         <div
           {...dragHandlers}
           {...threadLongPressHandlers}
           aria-current={isSelected ? 'true' : undefined}
+          data-unread={hasUnread ? 'true' : 'false'}
+          data-mv-mobile-row={mvMobileRow ? "" : undefined}
           className={cn(
             "relative group cursor-pointer select-none transition-shadow duration-200 overflow-hidden",
             rowTint ? rowTint : (
               isSelected
                 ? "bg-accent"
-                : "bg-background"
+                : mvRow && !hasUnread
+                  ? "bg-muted/60"
+                  : "bg-background"
             ),
             isSelected && !rowTint && "shadow-sm",
             !rowTint && !isSelected && !isChecked && "hover:bg-muted hover:shadow-sm",
             !rowTint && (isSelected || isChecked) && "hover:bg-accent hover:shadow-sm",
             rowTint && "hover:brightness-95 dark:hover:brightness-110",
-            hasUnread && !rowTint && !isSelected && "bg-accent/30",
+            hasUnread && !rowTint && !isSelected && !mvRow && !mvMobileRow && "bg-accent/30",
             isExpanded && "border-b border-border/50",
             isChecked && "ring-2 ring-primary/20",
             isChecked && !rowTint && "bg-accent/40",
@@ -855,7 +1012,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
             style={{ gap: 'var(--density-item-gap)', paddingBlock: 'var(--density-item-py)' }}
           >
             {/* Checkbox for thread selection - only for extra-compact density (no avatar) while in selection mode */}
-            {density === 'extra-compact' && selectedEmailIds.size > 0 && (
+            {!mvRow && density === 'extra-compact' && selectedEmailIds.size > 0 && (
               <button
                 onClick={handleThreadCheckboxClick}
                 role="checkbox"
@@ -878,7 +1035,18 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
               </button>
             )}
 
-            {density !== 'extra-compact' && (
+            {mvRow && (
+              <MvRowLead
+                checked={isChecked}
+                onToggleChecked={handleThreadCheckboxClick}
+                starred={!!hasStarred}
+                onToggleStar={onToggleStar ? () => onToggleStar(latestEmail) : undefined}
+                selectLabel={tBatch('select')}
+                starLabel={tHover('star')}
+              />
+            )}
+
+            {!mvRow && density !== 'extra-compact' && (
               <div className="relative flex-shrink-0 self-center">
                 <SelectableAvatar
                   name={avatarPerson?.name}
@@ -921,12 +1089,13 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
               </div>
             )}
 
-            {hasUnread && density === 'extra-compact' && (
+            {hasUnread && !mvRow && density === 'extra-compact' && (
               <UnreadDot besideAvatar={false} />
             )}
 
             <div className="flex-1 min-w-0">
               {isFocusedMailLayout ? (
+                <>
                 <div className="flex items-center justify-between gap-3">
                   <div className="flex min-w-0 flex-1 items-center gap-3">
                     {isUnifiedView && latestEmail.accountId && threadAccountColor && !tintListRowsByAccount && (
@@ -973,7 +1142,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
                   </div>
                   <div className="flex items-center gap-2.5 shrink-0">
                     {hasPinned && <StatusIcon icon={Pin} label={tStatus('pinned')} className="w-3.5 h-3.5 text-primary" />}
-                    {hasStarred && <StatusIcon icon={Star} label={tStatus('starred')} className="w-3.5 h-3.5 fill-amber-400 text-amber-400" />}
+                    {hasStarred && !mvRow && <StatusIcon icon={Star} label={tStatus('starred')} className="w-3.5 h-3.5 fill-amber-400 text-amber-400" />}
                     {hasAnswered && !hasForwarded && <StatusIcon icon={Reply} label={tStatus('replied')} className="w-3.5 h-3.5 text-muted-foreground" />}
                     {hasForwarded && !hasAnswered && <StatusIcon icon={Forward} label={tStatus('forwarded')} className="w-3.5 h-3.5 text-muted-foreground" />}
                     {hasAnswered && hasForwarded && (
@@ -1002,6 +1171,14 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
                     )}
                   </div>
                 </div>
+                {mvRow && (
+                  <RowChips
+                    email={latestEmail}
+                    loadAttachments={loadAttachments}
+                    onOpenAttachment={onOpenAttachment ? (a) => onOpenAttachment(latestEmail, a) : undefined}
+                  />
+                )}
+                </>
               ) : (
                 <>
                   <div className="flex items-center justify-between gap-2 mb-1">
@@ -1037,7 +1214,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
                         {hasPinned && (
                           <StatusIcon icon={Pin} label={tStatus('pinned')} className="w-3.5 h-3.5 text-primary" />
                         )}
-                        {hasStarred && (
+                        {hasStarred && !mvMobileRow && (
                           <StatusIcon icon={Star} label={tStatus('starred')} className="w-3.5 h-3.5 fill-amber-400 text-amber-400" />
                         )}
                         {hasAnswered && !hasForwarded && (
@@ -1077,6 +1254,13 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
                           {formatDate(latestEmail.receivedAt)}
                         </span>
                       )}
+                      {mvMobileRow && !(showPreview && density !== 'extra-compact' && density !== 'compact') && (
+                        <MvMobileStar
+                          starred={!!hasStarred}
+                          onToggle={onToggleStar ? () => onToggleStar(latestEmail) : undefined}
+                          label={tHover('star')}
+                        />
+                      )}
                     </div>
                   </div>
 
@@ -1099,14 +1283,24 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
                   </div>
 
                   {showPreview && density !== 'extra-compact' && density !== 'compact' && (
-                    <p className={cn(
-                      "text-sm leading-relaxed line-clamp-2",
-                      hasUnread
-                        ? "text-muted-foreground"
-                        : "text-muted-foreground/80"
-                    )}>
-                      {previewSnippet ? <SearchSnippetText snippet={previewSnippet} /> : (trimmedPreview || tEmailViewer('no_preview_available'))}
-                    </p>
+                    <div className={cn("flex min-w-0 items-center gap-1", !mvMobileRow && "contents")}>
+                      <p className={cn(
+                        "text-sm leading-relaxed",
+                        mvMobileRow ? "line-clamp-1 min-w-0 flex-1" : "line-clamp-2",
+                        hasUnread
+                          ? "text-muted-foreground"
+                          : "text-muted-foreground/80"
+                      )}>
+                        {previewSnippet ? <SearchSnippetText snippet={previewSnippet} /> : (trimmedPreview || tEmailViewer('no_preview_available'))}
+                      </p>
+                      {mvMobileRow && (
+                        <MvMobileStar
+                          starred={!!hasStarred}
+                          onToggle={onToggleStar ? () => onToggleStar(latestEmail) : undefined}
+                          label={tHover('star')}
+                        />
+                      )}
+                    </div>
                   )}
                   <RowChips
                     email={latestEmail}
diff --git a/components/icons/index.ts b/components/icons/index.ts
index 55ce5084a..c2c139d29 100644
--- a/components/icons/index.ts
+++ b/components/icons/index.ts
@@ -103,6 +103,7 @@ export {
   IconFolderX as FolderX,
   IconArrowForwardUp as Forward,
   IconWorld as Globe,
+  IconGridDots as Grid3x3,
   IconGripVertical as GripVertical,
   IconServer2 as HardDrive,
   IconH1 as Heading1,
diff --git a/components/keyboard-shortcuts-modal.tsx b/components/keyboard-shortcuts-modal.tsx
index dff59482b..bddd6041a 100644
--- a/components/keyboard-shortcuts-modal.tsx
+++ b/components/keyboard-shortcuts-modal.tsx
@@ -2,7 +2,8 @@
 
 import { useTranslations } from "next-intl";
 import { X, Keyboard } from "@/components/icons";
-import { KEYBOARD_SHORTCUTS } from "@/hooks/use-keyboard-shortcuts";
+import { KEYBOARD_SHORTCUTS, type ShortcutEntry } from "@/hooks/use-keyboard-shortcuts";
+import { useSettingsStore } from "@/stores/settings-store";
 import { cn } from "@/lib/utils";
 import { useFocusTrap } from "@/hooks/use-focus-trap";
 import { useTour } from "@/components/tour/tour-provider";
@@ -15,6 +16,10 @@ interface KeyboardShortcutsModalProps {
 export function KeyboardShortcutsModal({ isOpen, onClose }: KeyboardShortcutsModalProps) {
   const t = useTranslations();
   const { startTour } = useTour();
+  const interfaceLayout = useSettingsStore((state) => state.interfaceLayout);
+  // Rows that belong to one interface layout are listed only under it.
+  const shown = (entries: readonly ShortcutEntry[]) =>
+    entries.filter((entry) => !entry.layout || entry.layout === interfaceLayout);
 
   const modalRef = useFocusTrap({
     isActive: isOpen,
@@ -66,7 +71,7 @@ export function KeyboardShortcutsModal({ isOpen, onClose }: KeyboardShortcutsMod
                 {t("shortcuts.sections.navigation")}
               </h3>
               <div className="space-y-2">
-                {KEYBOARD_SHORTCUTS.navigation.map((shortcut) => (
+                {shown(KEYBOARD_SHORTCUTS.navigation).map((shortcut) => (
                   <ShortcutRow
                     key={shortcut.key}
                     shortcutKey={shortcut.key}
@@ -82,7 +87,7 @@ export function KeyboardShortcutsModal({ isOpen, onClose }: KeyboardShortcutsMod
                 {t("shortcuts.sections.actions")}
               </h3>
               <div className="space-y-2">
-                {KEYBOARD_SHORTCUTS.actions.map((shortcut) => (
+                {shown(KEYBOARD_SHORTCUTS.actions).map((shortcut) => (
                   <ShortcutRow
                     key={shortcut.key}
                     shortcutKey={shortcut.key}
@@ -98,7 +103,7 @@ export function KeyboardShortcutsModal({ isOpen, onClose }: KeyboardShortcutsMod
                 {t("shortcuts.sections.global")}
               </h3>
               <div className="grid grid-cols-1 md:grid-cols-2 gap-2">
-                {KEYBOARD_SHORTCUTS.global.map((shortcut) => (
+                {shown(KEYBOARD_SHORTCUTS.global).map((shortcut) => (
                   <ShortcutRow
                     key={shortcut.key}
                     shortcutKey={shortcut.key}
@@ -114,7 +119,7 @@ export function KeyboardShortcutsModal({ isOpen, onClose }: KeyboardShortcutsMod
                 {t("shortcuts.sections.threads")}
               </h3>
               <div className="grid grid-cols-1 md:grid-cols-2 gap-2">
-                {KEYBOARD_SHORTCUTS.threads.map((shortcut) => (
+                {shown(KEYBOARD_SHORTCUTS.threads).map((shortcut) => (
                   <ShortcutRow
                     key={shortcut.key}
                     shortcutKey={shortcut.key}
@@ -130,7 +135,7 @@ export function KeyboardShortcutsModal({ isOpen, onClose }: KeyboardShortcutsMod
                 {t("shortcuts.sections.composer")}
               </h3>
               <div className="grid grid-cols-1 md:grid-cols-2 gap-2">
-                {KEYBOARD_SHORTCUTS.composer.map((shortcut) => (
+                {shown(KEYBOARD_SHORTCUTS.composer).map((shortcut) => (
                   <ShortcutRow
                     key={shortcut.key}
                     shortcutKey={shortcut.key}
diff --git a/components/layout/__tests__/account-switcher-mountain-view.test.tsx b/components/layout/__tests__/account-switcher-mountain-view.test.tsx
new file mode 100644
index 000000000..b071cd5d2
--- /dev/null
+++ b/components/layout/__tests__/account-switcher-mountain-view.test.tsx
@@ -0,0 +1,121 @@
+import { render, screen, fireEvent, within } from '@testing-library/react';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import type { Mailbox } from '@/lib/jmap/types';
+
+// Mountain View rearranges the account popover: the account you are in
+// becomes a card at the top, the others become a list with the unread waiting
+// in each, and the merged inbox gets a row of its own. Outside Mountain View the
+// popover is the one the rail and the sidebar have always shown.
+
+const { AccountSwitcher } = await import('../account-switcher');
+const { useAccountStore } = await import('@/stores/account-store');
+const { useAuthStore } = await import('@/stores/auth-store');
+const { useEmailStore } = await import('@/stores/email-store');
+const { useSettingsStore } = await import('@/stores/settings-store');
+
+const inbox = (unread: number): Mailbox[] =>
+  [{ id: 'inbox', name: 'Inbox', role: 'inbox', totalEmails: 10, unreadEmails: unread }] as unknown as Mailbox[];
+
+function account(id: string, overrides: Record<string, unknown> = {}) {
+  return {
+    id,
+    label: `${id}@example.com`,
+    email: `${id}@example.com`,
+    username: `${id}@example.com`,
+    displayName: id.toUpperCase(),
+    serverUrl: 'https://mail.example.com',
+    avatarColor: '#336699',
+    cookieSlot: 0,
+    isConnected: true,
+    isDefault: id === 'a',
+    ...overrides,
+  };
+}
+
+const openPopover = () => fireEvent.click(screen.getByTestId('account-switcher'));
+
+describe('AccountSwitcher under Mountain View', () => {
+  beforeEach(() => {
+    useAccountStore.setState({ accounts: [account('a'), account('b')] } as never);
+    useAuthStore.setState({ activeAccountId: 'a' } as never);
+    useEmailStore.setState({ mailboxes: inbox(3), accountMailboxes: { b: inbox(5) } } as never);
+    useSettingsStore.setState({ interfaceLayout: 'mountain-view' } as never);
+  });
+
+  it('leads with the active account and does not repeat it in the list', () => {
+    render(<AccountSwitcher variant="header" />);
+    openPopover();
+
+    const options = screen.getAllByTestId('account-option');
+    expect(options).toHaveLength(1);
+    expect(options[0]).toHaveAttribute('data-account-id', 'b');
+    // The active address is still on screen - as the card, not as a row.
+    expect(screen.getAllByText('a@example.com').length).toBeGreaterThan(0);
+  });
+
+  it('draws plain rows: no colour stripe, no server line', () => {
+    render(<AccountSwitcher variant="header" />);
+    openPopover();
+
+    const row = screen.getByTestId('account-option');
+    expect(row.getAttribute('style') ?? '').not.toMatch(/border/);
+    // Tailwind's `hidden`: jsdom has no style sheet to compute visibility from.
+    expect(within(row).getByText('mail.example.com').closest('.hidden')).not.toBeNull();
+  });
+
+  it('keeps the server line for an account in trouble', () => {
+    useAccountStore.setState({ accounts: [account('a'), account('b', { hasError: true })] } as never);
+    render(<AccountSwitcher variant="header" />);
+    openPopover();
+
+    expect(within(screen.getByTestId('account-option')).getByText('mail.example.com').closest('.hidden')).toBeNull();
+  });
+
+  it('offers add-account and sign-out-of-all as a pair of pills', () => {
+    render(<AccountSwitcher variant="header" />);
+    openPopover();
+
+    const actions = document.querySelector('[data-mv-account-actions]');
+    expect(actions).not.toBeNull();
+    expect(actions!.querySelectorAll('button')).toHaveLength(2);
+    expect(screen.getAllByTestId('add-account')).toHaveLength(1);
+  });
+
+  it('puts the unread waiting in the other account next to it', () => {
+    render(<AccountSwitcher variant="header" />);
+    openPopover();
+
+    expect(within(screen.getByTestId('account-option')).getByText('5')).toBeInTheDocument();
+  });
+
+  it('offers the merged inbox, totalling every connected account, when one is reachable', () => {
+    const onSelectAllInboxes = vi.fn();
+    render(<AccountSwitcher variant="header" onSelectAllInboxes={onSelectAllInboxes} />);
+    openPopover();
+
+    const row = screen.getByTestId('all-inboxes');
+    expect(within(row).getByText('8')).toBeInTheDocument();
+
+    fireEvent.click(row);
+    expect(onSelectAllInboxes).toHaveBeenCalledOnce();
+    // Choosing it closes the popover, as switching account does.
+    expect(screen.queryByTestId('all-inboxes')).toBeNull();
+  });
+
+  it('draws no merged-inbox row when the caller has nowhere to send it', () => {
+    render(<AccountSwitcher variant="header" />);
+    openPopover();
+
+    expect(screen.queryByTestId('all-inboxes')).toBeNull();
+  });
+
+  it('leaves the default layout listing every account, unread-free', () => {
+    useSettingsStore.setState({ interfaceLayout: 'default' } as never);
+    render(<AccountSwitcher variant="header" onSelectAllInboxes={vi.fn()} />);
+    openPopover();
+
+    expect(screen.getAllByTestId('account-option')).toHaveLength(2);
+    expect(screen.queryByTestId('all-inboxes')).toBeNull();
+    expect(screen.queryByText('5')).toBeNull();
+  });
+});
diff --git a/components/layout/__tests__/sidebar-mountain-view-flat-list.test.tsx b/components/layout/__tests__/sidebar-mountain-view-flat-list.test.tsx
new file mode 100644
index 000000000..33899b6ec
--- /dev/null
+++ b/components/layout/__tests__/sidebar-mountain-view-flat-list.test.tsx
@@ -0,0 +1,136 @@
+import { render, screen, fireEvent } from '@testing-library/react';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import type { Mailbox } from '@/lib/jmap/types';
+
+// Under Mountain View the sidebar is one flat list: inbox, sent and drafts,
+// then a single "More" that reveals the folders you made, the shared ones and
+// the labels. Outside Mountain View the "Folders" / "Tags" sections stay as they
+// are, headings and all.
+
+vi.mock('@/components/plugins/plugin-slot', () => ({ PluginSlot: () => null }));
+vi.mock('@/components/tour/tour-provider', () => ({
+  useTour: () => ({ startTour: vi.fn(), resetTourCompletion: vi.fn(), activeTour: null, endTour: vi.fn(), registerStep: vi.fn() }),
+}));
+vi.mock('@/contexts/drag-drop-context', () => ({
+  useDragDropContext: () => ({ isDragging: false }),
+}));
+vi.mock('@/hooks/use-mailbox-drop', () => ({
+  useMailboxDrop: () => ({ dropHandlers: {}, isValidDropTarget: false, isInvalidDropTarget: false }),
+}));
+vi.mock('@/hooks/use-tag-drop', () => ({
+  useTagDrop: () => ({ dropHandlers: {}, isValidDropTarget: false }),
+}));
+vi.mock('../account-switcher', () => ({ AccountSwitcher: () => null }));
+
+const { Sidebar } = await import('../sidebar');
+const { useSettingsStore } = await import('@/stores/settings-store');
+const { useUIStore } = await import('@/stores/ui-store');
+
+const mailboxes: Mailbox[] = [
+  { id: 'inbox', name: 'Inbox', role: 'inbox', parentId: null, totalEmails: 0, unreadEmails: 0, sortOrder: 0, myRights: { mayAddItems: true } },
+  { id: 'sent', name: 'Sent', role: 'sent', parentId: null, totalEmails: 0, unreadEmails: 0, sortOrder: 1, myRights: { mayAddItems: true } },
+  { id: 'drafts', name: 'Drafts', role: 'drafts', parentId: null, totalEmails: 0, unreadEmails: 0, sortOrder: 2, myRights: { mayAddItems: true } },
+  { id: 'trash', name: 'Trash', role: 'trash', parentId: null, totalEmails: 0, unreadEmails: 0, sortOrder: 3, myRights: { mayAddItems: true } },
+  { id: 'receipts', name: 'Receipts', parentId: null, totalEmails: 0, unreadEmails: 0, sortOrder: 4, myRights: { mayAddItems: true } },
+] as unknown as Mailbox[];
+
+/** Rows carry their untranslated folder name; the visible label is localised. */
+const folderRow = (name: string) => document.querySelector(`[data-folder-name="${name}"]`);
+
+describe('Sidebar under Mountain View', () => {
+  beforeEach(() => {
+    useUIStore.setState({ sidebarCollapsed: false } as never);
+    useSettingsStore.setState({
+      emailKeywords: [{ id: 'work', label: 'Work', color: 'blue' }],
+      enableUnifiedMailbox: false,
+      hideAccountSwitcher: true,
+    } as never);
+  });
+
+  it('drops the Folders heading and holds the rest behind More', () => {
+    render(<Sidebar mailboxes={mailboxes} selectedMailbox="inbox" mvShell />);
+
+    expect(screen.queryByText('folders')).toBeNull();
+    expect(screen.getByText('show_more')).toBeInTheDocument();
+    expect(folderRow('Receipts')).toBeNull();
+    expect(folderRow('Trash')).toBeNull();
+    // The labels heading goes with them: it shows only once expanded.
+    expect(screen.queryByText('tags')).toBeNull();
+  });
+
+  it('keeps the places mail actually goes in view', () => {
+    render(<Sidebar mailboxes={mailboxes} selectedMailbox="inbox" mvShell />);
+
+    expect(folderRow('Inbox')).not.toBeNull();
+    expect(folderRow('Sent')).not.toBeNull();
+    expect(folderRow('Drafts')).not.toBeNull();
+  });
+
+  it('lists Starred right under the Inbox, and opens it', () => {
+    const onOpenStarred = vi.fn();
+    const { container } = render(
+      <Sidebar mailboxes={mailboxes} selectedMailbox="inbox" mvShell onOpenStarred={onOpenStarred} />,
+    );
+
+    const rows = [...container.querySelectorAll('[data-folder-name]')].map((r) => r.getAttribute('data-folder-name'));
+    expect(rows.indexOf('mv-starred')).toBe(rows.indexOf('Inbox') + 1);
+    fireEvent.click(container.querySelector('[data-folder-name="mv-starred"] button:last-of-type')!);
+    expect(onOpenStarred).toHaveBeenCalledTimes(1);
+  });
+
+  it('has no Starred row outside Mountain View', () => {
+    const { container } = render(<Sidebar mailboxes={mailboxes} selectedMailbox="inbox" onOpenStarred={vi.fn()} />);
+    expect(container.querySelector('[data-folder-name="mv-starred"]')).toBeNull();
+  });
+
+  it('reveals the folders and the labels together, and takes them back', () => {
+    render(<Sidebar mailboxes={mailboxes} selectedMailbox="inbox" mvShell />);
+
+    fireEvent.click(screen.getByText('show_more'));
+    expect(folderRow('Receipts')).not.toBeNull();
+    expect(folderRow('Trash')).not.toBeNull();
+    expect(screen.getByText('tags')).toBeInTheDocument();
+
+    fireEvent.click(screen.getByText('show_fewer'));
+    expect(folderRow('Receipts')).toBeNull();
+  });
+
+  it('leaves the default layout its sections and every folder', () => {
+    render(<Sidebar mailboxes={mailboxes} selectedMailbox="inbox" />);
+
+    expect(screen.getByText('folders')).toBeInTheDocument();
+    expect(screen.queryByText('show_more')).toBeNull();
+    expect(folderRow('Receipts')).not.toBeNull();
+    expect(screen.getByText('tags')).toBeInTheDocument();
+  });
+});
+
+describe('Sidebar collapsed rail under Mountain View', () => {
+  beforeEach(() => {
+    useUIStore.setState({ sidebarCollapsed: true } as never);
+    useSettingsStore.setState({ emailKeywords: [], hideAccountSwitcher: true } as never);
+  });
+
+  it('peeks the full list out on hover and puts it away again', () => {
+    const { container } = render(<Sidebar mailboxes={mailboxes} selectedMailbox="inbox" mvShell />);
+    const rail = container.firstElementChild as HTMLElement;
+
+    expect(rail).not.toHaveAttribute('data-mv-rail-peek');
+
+    fireEvent.mouseEnter(rail);
+    expect(rail).toHaveAttribute('data-mv-rail-peek');
+    // Peeking means the list is legible, i.e. no longer icon-only.
+    expect(screen.getByText('show_more')).toBeInTheDocument();
+
+    fireEvent.mouseLeave(rail);
+    expect(rail).not.toHaveAttribute('data-mv-rail-peek');
+  });
+
+  it('does not peek outside Mountain View', () => {
+    const { container } = render(<Sidebar mailboxes={mailboxes} selectedMailbox="inbox" />);
+    const rail = container.firstElementChild as HTMLElement;
+
+    fireEvent.mouseEnter(rail);
+    expect(rail).not.toHaveAttribute('data-mv-rail-peek');
+  });
+});
diff --git a/components/layout/account-switcher.tsx b/components/layout/account-switcher.tsx
index b330ba8c8..07f760119 100644
--- a/components/layout/account-switcher.tsx
+++ b/components/layout/account-switcher.tsx
@@ -2,11 +2,15 @@
 
 import { useState, useRef, useEffect, useLayoutEffect, useCallback, useMemo, useId } from "react";
 import { createPortal } from "react-dom";
-import { Check, Plus, LogOut, Star, ChevronDown, AlertCircle, GripVertical, X } from "@/components/icons";
+import { Check, Plus, LogOut, Mails, Star, ChevronDown, AlertCircle, GripVertical, X } from "@/components/icons";
 import { useTranslations } from "next-intl";
+import type { Mailbox } from "@/lib/jmap/types";
 import { useAccountStore, type AccountEntry } from "@/stores/account-store";
 import { useAuthStore } from "@/stores/auth-store";
+import { useEmailStore } from "@/stores/email-store";
+import { useSettingsStore } from "@/stores/settings-store";
 import { getMaxAccounts, sortDefaultFirst, reorderNonDefaultIds } from "@/lib/account-utils";
+import { inboxUnread, totalInboxUnread } from "@/lib/account-inbox-unread";
 import { isDocumentRTL } from "@/i18n/direction";
 import { cn } from "@/lib/utils";
 import { useRouter } from "@/i18n/navigation";
@@ -18,22 +22,50 @@ interface AccountSwitcherProps {
   /** "rail" = small avatar only (NavigationRail), "expanded" = avatar + name + email (Sidebar) */
   variant?: "rail" | "expanded" | "header";
   className?: string;
+  /**
+   * Mountain View only: opens the one list that spans every account. It sits
+   * at the head of the account popover, above the addresses it merges,
+   * because it is the alternative to picking one of them. Omitted when the
+   * unified view is off or out of reach, and then no row is drawn.
+   */
+  onSelectAllInboxes?: () => void;
+  /** Whether that merged list is the one currently on screen. */
+  allInboxesSelected?: boolean;
 }
 
-function AccountAvatar({ account, size = "sm" }: { account: AccountEntry; size?: "sm" | "md" }) {
+function AccountAvatar({ account, size = "sm" }: { account: AccountEntry; size?: "sm" | "md" | "xl" }) {
   return (
     <Avatar
       name={account.displayName || account.label}
       email={account.email || account.username}
       size="sm"
-      className={cn("flex-shrink-0", size === "md" && "w-9 h-9 text-sm")}
+      className={cn(
+        "flex-shrink-0",
+        size === "md" && "w-9 h-9 text-sm",
+        size === "xl" && "!w-20 !h-20 !text-2xl"
+      )}
       disableFavicon
       fallbackColor={account.avatarColor}
     />
   );
 }
 
-export function AccountSwitcher({ variant = "rail", className }: AccountSwitcherProps) {
+/** The popover's unread badge: a count, capped, or nothing at all when there is none. */
+function UnreadBadge({ count }: { count: number | undefined }) {
+  if (!count) return null;
+  return (
+    <span className="ms-auto shrink-0 text-xs font-medium tabular-nums text-primary">
+      {count > 999 ? "999+" : count}
+    </span>
+  );
+}
+
+export function AccountSwitcher({
+  variant = "rail",
+  className,
+  onSelectAllInboxes,
+  allInboxesSelected = false,
+}: AccountSwitcherProps) {
   const t = useTranslations("sidebar");
   const router = useRouter();
   const [open, setOpen] = useState(false);
@@ -50,6 +82,13 @@ export function AccountSwitcher({ variant = "rail", className }: AccountSwitcher
     triggerRef: buttonRef,
   });
 
+  // The header avatar is Mountain View's account control; the same component
+  // in the rail and the sidebar keeps the list it has always had, so the
+  // default layout is untouched.
+  const mvPopover = useSettingsStore((s) => s.interfaceLayout === "mountain-view") && variant === "header";
+  const accountMailboxes = useEmailStore((s) => s.accountMailboxes);
+  const ownMailboxes = useEmailStore((s) => s.mailboxes);
+
   const accounts = useAccountStore((s) => s.accounts);
   const setDefaultAccount = useAccountStore((s) => s.setDefaultAccount);
   const reorderAccounts = useAccountStore((s) => s.reorderAccounts);
@@ -203,6 +242,23 @@ export function AccountSwitcher({ variant = "rail", className }: AccountSwitcher
   const displayName = toUnicodeEmail(activeAccount?.displayName || activeAccount?.label || "");
   const displayEmail = toUnicodeEmail(activeAccount?.email || activeAccount?.username || "");
 
+  // Mountain View leads its popover with the account you are already in - large avatar,
+  // name, address - and lists only the others underneath, since choosing one is
+  // the point of opening it. Every row carries the unread waiting there, so the
+  // choice can be made without visiting each account in turn.
+  const listedAccounts = mvPopover
+    ? displayAccounts.filter((account) => account.id !== activeAccountId)
+    : displayAccounts;
+  const unreadByAccount: Record<string, Mailbox[] | undefined> = activeAccountId
+    ? { ...accountMailboxes, [activeAccountId]: ownMailboxes }
+    : accountMailboxes;
+  const unreadFor = (account: AccountEntry) =>
+    mvPopover ? inboxUnread(unreadByAccount[account.id]) : undefined;
+  const allInboxesUnread = totalInboxUnread(
+    accounts.filter((account) => account.isConnected).map((account) => account.id),
+    unreadByAccount
+  );
+
   return (
     <>
       <button
@@ -250,15 +306,58 @@ export function AccountSwitcher({ variant = "rail", className }: AccountSwitcher
         <div
           ref={popoverRef}
           style={popoverStyle}
-          className="w-72 rounded-lg border border-border bg-background text-foreground shadow-lg z-50 overflow-hidden"
+          className={cn(
+            "border border-border bg-background text-foreground shadow-lg z-50 overflow-hidden",
+            // Width and radius come from the layout's own tokens, keyed on the
+            // attribute below; only the elevation differs in markup.
+            mvPopover ? "shadow-xl" : "w-72 rounded-lg"
+          )}
+          data-mv-account-popover={mvPopover ? "" : undefined}
           role="menu"
           id={menuId}
           aria-label={t("switch_account")}
           onKeyDown={handleMenuKeyDown}
         >
-          {/* Account List */}
-          <div className="py-1 max-h-64 overflow-y-auto">
-            {displayAccounts.map((account) => {
+          {mvPopover && activeAccount && (
+            <div className="flex flex-col items-center gap-1 px-4 pt-6 pb-4 text-center">
+              <AccountAvatar account={activeAccount} size="xl" />
+              <p className="mt-2 text-base font-medium truncate max-w-full">{displayName}</p>
+              <p className="text-sm text-muted-foreground truncate max-w-full">{displayEmail}</p>
+            </div>
+          )}
+
+          {mvPopover && onSelectAllInboxes && (
+            <div className="border-t border-border">
+              <button
+                type="button"
+                role="menuitem"
+                data-testid="all-inboxes"
+                onClick={() => {
+                  setOpen(false);
+                  onSelectAllInboxes();
+                }}
+                className={cn(
+                  "w-full flex items-center gap-3 px-4 py-3 text-start text-sm transition-colors",
+                  allInboxesSelected ? "bg-accent/50 font-medium" : "hover:bg-muted"
+                )}
+              >
+                <Mails className="w-4 h-4 flex-shrink-0 text-muted-foreground" />
+                <span className="truncate">{t("unified_inbox")}</span>
+                <UnreadBadge count={allInboxesUnread} />
+              </button>
+            </div>
+          )}
+
+          {/* Account List. Under Mountain View the active account is already the
+              card above, so with a single login there is no list to draw. */}
+          <div
+            className={cn(
+              "py-1 max-h-64 overflow-y-auto",
+              mvPopover && "border-t border-border",
+              mvPopover && listedAccounts.length === 0 && "hidden"
+            )}
+          >
+            {listedAccounts.map((account) => {
               const isActive = account.id === activeAccountId;
               const isDraggable = !account.isDefault && accounts.length > 2;
               return (
@@ -304,11 +403,14 @@ export function AccountSwitcher({ variant = "rail", className }: AccountSwitcher
                       {account.isDefault && (
                         <Star className="w-3 h-3 text-amber-500 flex-shrink-0 fill-amber-500" />
                       )}
+                      <UnreadBadge count={unreadFor(account)} />
                     </div>
                     <p className="text-xs text-muted-foreground truncate">
                       {toUnicodeEmail(account.email || account.username)}
                     </p>
-                    <div className="flex items-center gap-1 mt-0.5">
+                    {/* Server and connection state: Mountain View keeps the line
+                        only for an account in trouble. */}
+                    <div className={cn("flex items-center gap-1 mt-0.5", mvPopover && !account.hasError && "hidden")}>
                       {account.hasError ? (
                         <AlertCircle className="w-3 h-3 text-destructive" />
                       ) : (
@@ -348,8 +450,36 @@ export function AccountSwitcher({ variant = "rail", className }: AccountSwitcher
             })}
           </div>
 
+          {/* Mountain View: "Add another account" and "Sign out of all accounts" as two
+              pills side by side. */}
+          {mvPopover && (
+            <div className="flex flex-wrap items-center justify-center gap-2 border-t border-border px-4 py-3" data-mv-account-actions="">
+              {accounts.length < getMaxAccounts() && (
+                <button
+                  onClick={handleAddAccount}
+                  data-testid="add-account"
+                  className="flex items-center gap-2 rounded-full border border-border px-4 py-2 text-sm hover:bg-muted transition-colors"
+                  role="menuitem"
+                >
+                  <Plus className="w-4 h-4" />
+                  {t("add_account")}
+                </button>
+              )}
+              {accounts.length > 1 && (
+                <button
+                  onClick={handleLogoutAll}
+                  className="flex items-center gap-2 rounded-full border border-border px-4 py-2 text-sm hover:bg-muted transition-colors"
+                  role="menuitem"
+                >
+                  <LogOut className="w-4 h-4" />
+                  {t("sign_out_all")}
+                </button>
+              )}
+            </div>
+          )}
+
           {/* Separator + Add Account */}
-          {accounts.length < getMaxAccounts() && (
+          {!mvPopover && accounts.length < getMaxAccounts() && (
             <div className="border-t border-border">
               <button
                 onClick={handleAddAccount}
@@ -383,7 +513,7 @@ export function AccountSwitcher({ variant = "rail", className }: AccountSwitcher
               <LogOut className="w-4 h-4" />
               {t("sign_out_of", { account: displayEmail })}
             </button>
-            {accounts.length > 1 && (
+            {!mvPopover && accounts.length > 1 && (
               <button
                 onClick={handleLogoutAll}
                 className="w-full flex items-center gap-2 px-3 py-2 text-sm text-destructive hover:bg-muted transition-colors"
diff --git a/components/layout/mobile-header.tsx b/components/layout/mobile-header.tsx
index 7ea53a54b..b9e71a9ac 100644
--- a/components/layout/mobile-header.tsx
+++ b/components/layout/mobile-header.tsx
@@ -3,6 +3,7 @@
 import { Menu, ArrowLeft, Plus, Search, X } from "@/components/icons";
 import { Button } from "@/components/ui/button";
 import { useUIStore } from "@/stores/ui-store";
+import { useSettingsStore } from "@/stores/settings-store";
 import { useIsDesktop } from "@/hooks/use-media-query";
 import { cn } from "@/lib/utils";
 import { useTranslations } from "next-intl";
@@ -29,6 +30,9 @@ interface MobileHeaderProps {
   onClearSearch?: () => void;
   /** Whether a query is currently applied, which reveals the clear button. */
   searchActive?: boolean;
+  /** Mountain View: opens the merged across-accounts inbox from the avatar's popover. */
+  onSelectAllInboxes?: () => void;
+  allInboxesSelected?: boolean;
 }
 
 export function MobileHeader({
@@ -43,9 +47,12 @@ export function MobileHeader({
   searchPlaceholder,
   onClearSearch,
   searchActive = false,
+  onSelectAllInboxes,
+  allInboxesSelected = false,
 }: MobileHeaderProps) {
   const t = useTranslations('sidebar');
   const { toggleSidebar, goBack, sidebarOpen } = useUIStore();
+  const mountainView = useSettingsStore((state) => state.interfaceLayout === 'mountain-view');
   // Pane-aware: in Pro split mode the viewport is desktop-wide while the
   // pane is narrow. The Tailwind `lg:hidden` variant alone would never fire
   // there, so we additionally hide via JS when the surrounding pane is
@@ -65,8 +72,12 @@ export function MobileHeader({
 
   return (
     <header
+      data-mobile-mail-header=""
       className={cn(
-        "flex items-center justify-between px-4 h-14 border-b border-border bg-background shrink-0",
+        "flex items-center justify-between h-14 shrink-0",
+        mountainView
+          ? "mx-2 mt-2 mb-1 rounded-full border-0 bg-muted px-2 shadow-sm"
+          : "border-b border-border bg-background px-4",
         className
       )}
     >
@@ -101,7 +112,13 @@ export function MobileHeader({
       {onOpenSearch && (
         /* Not a single button: the clear control is a button of its own, and
            nesting one inside another is invalid markup. */
-        <div className="flex-1 min-w-0 h-10 mx-1 flex items-center rounded-full bg-muted ps-3 pe-1">
+        <div
+          data-mobile-mail-search=""
+          className={cn(
+            "flex-1 min-w-0 h-10 flex items-center rounded-full pe-1",
+            mountainView ? "mx-0 bg-transparent ps-2" : "mx-1 bg-muted ps-3"
+          )}
+        >
           <button
             type="button"
             onClick={onOpenSearch}
@@ -153,7 +170,11 @@ export function MobileHeader({
             opening the drawer. Last in this group so it sits on the far
             edge — opposite the menu button, and mirrored under RTL because
             the header is laid out with flex rather than fixed sides. */}
-        <AccountSwitcher variant="header" />
+        <AccountSwitcher
+          variant="header"
+          onSelectAllInboxes={onSelectAllInboxes}
+          allInboxesSelected={allInboxesSelected}
+        />
       </div>
     </header>
   );
diff --git a/components/layout/mv-top-bar.tsx b/components/layout/mv-top-bar.tsx
new file mode 100644
index 000000000..ae1a3a0a3
--- /dev/null
+++ b/components/layout/mv-top-bar.tsx
@@ -0,0 +1,335 @@
+"use client";
+
+import { useCallback, useEffect, useRef, useState } from "react";
+import {
+  BookUser,
+  Calendar,
+  Filter,
+  Grid3x3,
+  HardDrive,
+  Keyboard,
+  Mail,
+  Menu,
+  Settings,
+  iconForName,
+} from "@/components/icons";
+import type { AppIcon as AppIconType } from "@/components/icons";
+import { useTranslations } from "next-intl";
+import { Link, usePathname } from "@/i18n/navigation";
+import { useAuthStore } from "@/stores/auth-store";
+import { useCalendarStore } from "@/stores/calendar-store";
+import { useConfig } from "@/hooks/use-config";
+import { usePolicyStore } from "@/stores/policy-store";
+import { useResolvedSidebarApps } from "@/hooks/use-resolved-sidebar-apps";
+import { useThemeStore } from "@/stores/theme-store";
+import { useUIStore } from "@/stores/ui-store";
+import { useMenuNavigation } from "@/hooks/use-menu-navigation";
+import { withBasePath } from "@/lib/browser-navigation";
+import { cn } from "@/lib/utils";
+import { AccountSwitcher } from "@/components/layout/account-switcher";
+import { SearchBox, type ContactSearchField } from "@/components/search/search-box";
+import type { ContactSuggestion } from "@/lib/search-suggestions";
+
+interface MvTopBarProps {
+  searchQuery: string;
+  onSearchQueryChange: (value: string) => void;
+  onSearchSubmit: (query: string) => void;
+  onSearchClear: () => void;
+  onSelectContact: (contact: ContactSuggestion, field: ContactSearchField) => void;
+  /** Opens the advanced-filter panel that lives under the message list. */
+  onToggleFilters: () => void;
+  filtersOpen: boolean;
+  activeFilterCount: number;
+  searchDisabled?: boolean;
+  onShowShortcuts?: () => void;
+  onManageApps?: () => void;
+  onInlineApp?: (appId: string, url: string, name: string) => void;
+  onCloseInlineApp?: () => void;
+  activeAppId?: string | null;
+  /** Opens the merged across-accounts inbox from the account popover. */
+  onSelectAllInboxes?: () => void;
+  allInboxesSelected?: boolean;
+  /**
+   * Receives the node under the search field that the advanced-filter panel is
+   * portalled into, so the panel drops from the field itself; without this
+   * the panel would stay behind in the message-list column, two bars away from
+   * the button that opens it.
+   */
+  onFilterAnchorChange?: (node: HTMLDivElement | null) => void;
+}
+
+/**
+ * Mountain View's global header: one 64px row that owns the hamburger, the
+ * brand, the search field and the account cluster. It only renders on
+ * desktop under `interfaceLayout === 'mountain-view'`; the default layout keeps
+ * search inside the list column and navigation in the left rail, and neither
+ * of those is touched here.
+ */
+export function MvTopBar({
+  searchQuery,
+  onSearchQueryChange,
+  onSearchSubmit,
+  onSearchClear,
+  onSelectContact,
+  onToggleFilters,
+  filtersOpen,
+  activeFilterCount,
+  searchDisabled = false,
+  onShowShortcuts,
+  onManageApps,
+  onInlineApp,
+  onCloseInlineApp,
+  activeAppId,
+  onSelectAllInboxes,
+  allInboxesSelected = false,
+  onFilterAnchorChange,
+}: MvTopBarProps) {
+  const t = useTranslations("sidebar");
+  const tSearch = useTranslations("advanced_search");
+  const pathname = usePathname();
+  const { appName, appLogoLightUrl, appLogoDarkUrl } = useConfig();
+  const resolvedTheme = useThemeStore((s) => s.resolvedTheme);
+  const toggleSidebarCollapsed = useUIStore((s) => s.toggleSidebarCollapsed);
+
+  const client = useAuthStore((s) => s.client);
+  const { supportsCalendar } = useCalendarStore();
+  const calendarEnabled = usePolicyStore((s) => s.isFeatureEnabled("calendarEnabled"));
+  const contactsEnabled = usePolicyStore((s) => s.isFeatureEnabled("contactsEnabled"));
+  const filesEnabled = usePolicyStore((s) => s.isFeatureEnabled("filesEnabled"));
+  const sidebarApps = useResolvedSidebarApps();
+
+  const [appsOpen, setAppsOpen] = useState(false);
+  const appsButtonRef = useRef<HTMLButtonElement>(null);
+  const closeApps = useCallback(() => setAppsOpen(false), []);
+  const { menuRef: appsMenuRef, onKeyDown: onAppsKeyDown } = useMenuNavigation<HTMLDivElement>({
+    open: appsOpen,
+    onClose: closeApps,
+    triggerRef: appsButtonRef,
+  });
+
+  useEffect(() => {
+    if (!appsOpen) return;
+    const onPointerDown = (e: MouseEvent) => {
+      if (
+        appsButtonRef.current?.contains(e.target as Node) ||
+        appsMenuRef.current?.contains(e.target as Node)
+      ) return;
+      setAppsOpen(false);
+    };
+    document.addEventListener("mousedown", onPointerDown);
+    return () => document.removeEventListener("mousedown", onPointerDown);
+  }, [appsOpen, appsMenuRef]);
+
+  const apps: Array<{ id: string; icon: AppIconType; label: string; href: string }> = [
+    { id: "mail", icon: Mail, label: t("mail"), href: "/" },
+    ...(supportsCalendar && calendarEnabled
+      ? [{ id: "calendar", icon: Calendar, label: t("calendar"), href: "/calendar" }]
+      : []),
+    ...((client?.supportsContacts() ?? false) && contactsEnabled
+      ? [{ id: "contacts", icon: BookUser, label: t("contacts"), href: "/contacts" }]
+      : []),
+    ...((client?.supportsFiles() ?? false) && filesEnabled
+      ? [{ id: "files", icon: HardDrive, label: t("files"), href: "/files" }]
+      : []),
+    { id: "settings", icon: Settings, label: t("settings"), href: "/settings" },
+  ];
+
+  const isActive = (href: string) =>
+    !activeAppId && (href === "/" ? pathname === "/" || pathname === "" : pathname.startsWith(href));
+
+  const logoUrl = withBasePath(
+    resolvedTheme === "dark" ? appLogoDarkUrl || appLogoLightUrl : appLogoLightUrl || appLogoDarkUrl
+  );
+
+  return (
+    <header
+      className="mv-topbar flex items-center h-16 gap-2 ps-1 pe-4 shrink-0 bg-background"
+      data-mv-topbar=""
+    >
+      {/* Brand block: occupies the sidebar's own column width */}
+      <div className="flex items-center gap-1 shrink-0">
+        <button
+          type="button"
+          onClick={toggleSidebarCollapsed}
+          className="grid place-items-center w-12 h-12 rounded-full text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
+          aria-label={t("mobile.toggle_menu")}
+        >
+          <Menu className="w-5 h-5" />
+        </button>
+        <Link href="/" className="flex items-center gap-2 pe-4 min-w-0" aria-label={appName}>
+          {logoUrl ? <img src={logoUrl} alt="" className="w-8 h-8 object-contain" /> : null}
+          <span className="text-[22px] leading-none text-foreground/80 truncate">{appName}</span>
+        </Link>
+      </div>
+
+      {/* Search: left-anchored and capped, not centred */}
+      <div className="mv-topbar-search relative flex items-center gap-1 flex-1 min-w-0 max-w-[720px]">
+        <SearchBox
+          value={searchQuery}
+          onChange={onSearchQueryChange}
+          onSubmit={onSearchSubmit}
+          onClear={onSearchClear}
+          onSelectContact={onSelectContact}
+          disabled={searchDisabled}
+        />
+        <button
+          type="button"
+          onClick={onToggleFilters}
+          disabled={searchDisabled}
+          // Inside the field's trailing end, next to the typed query.
+          className={cn(
+            "absolute end-1 top-1/2 -translate-y-1/2 z-10 grid place-items-center w-10 h-10 rounded-full transition-colors",
+            searchDisabled && "opacity-50 cursor-not-allowed",
+            filtersOpen || activeFilterCount > 0
+              ? "bg-primary/10 text-primary"
+              : "text-muted-foreground hover:bg-muted hover:text-foreground"
+          )}
+          title={tSearch("toggle_filters")}
+          aria-label={tSearch("toggle_filters")}
+        >
+          <Filter className="w-5 h-5" />
+          {!filtersOpen && activeFilterCount > 0 && (
+            <span className="absolute top-1.5 end-1.5 grid place-items-center w-4 h-4 text-[10px] font-bold rounded-full bg-primary text-primary-foreground">
+              {activeFilterCount}
+            </span>
+          )}
+        </button>
+
+        {/* Anchor for the advanced-filter panel: the search field's own box,
+            filter button included, so the panel shares the field's edges. It
+            only marks the spot; the panel itself is drawn at the end of <body>. */}
+        <div
+          ref={onFilterAnchorChange}
+          aria-hidden
+          data-mv-filter-anchor=""
+          className="pointer-events-none absolute start-0 end-0 top-full h-0"
+        />
+      </div>
+
+      {/* Spacer keeps the right cluster pinned while search stays left */}
+      <div className="flex-1 min-w-0" />
+
+      <div className="flex items-center gap-1 shrink-0">
+        {onShowShortcuts && (
+          <button
+            type="button"
+            onClick={onShowShortcuts}
+            className="grid place-items-center w-12 h-12 rounded-full text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
+            title={t("keyboard_shortcuts")}
+            aria-label={t("keyboard_shortcuts")}
+          >
+            <Keyboard className="w-5 h-5" />
+          </button>
+        )}
+        <Link
+          href="/settings"
+          className="grid place-items-center w-12 h-12 rounded-full text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
+          title={t("settings")}
+          aria-label={t("settings")}
+        >
+          <Settings className="w-5 h-5" />
+        </Link>
+
+        <div className="relative">
+          <button
+            ref={appsButtonRef}
+            type="button"
+            onClick={() => setAppsOpen((v) => !v)}
+            className={cn(
+              "grid place-items-center w-12 h-12 rounded-full transition-colors",
+              appsOpen
+                ? "bg-muted text-foreground"
+                : "text-muted-foreground hover:bg-muted hover:text-foreground"
+            )}
+            title={t("add_app")}
+            aria-label={t("add_app")}
+            aria-haspopup="menu"
+            aria-expanded={appsOpen}
+          >
+            <Grid3x3 className="w-5 h-5" />
+          </button>
+          {appsOpen && (
+            <div
+              ref={appsMenuRef}
+              onKeyDown={onAppsKeyDown}
+              role="menu"
+              aria-label={t("nav_label")}
+              className="absolute end-0 top-full mt-1 z-50 w-72 max-h-[70vh] overflow-y-auto rounded-2xl border border-border bg-popover p-3 shadow-xl"
+            >
+              <div className="grid grid-cols-3 gap-1">
+                {apps.map((app) => {
+                  const Icon = app.icon;
+                  return (
+                    <Link
+                      key={app.id}
+                      href={app.href}
+                      role="menuitem"
+                      onClick={() => {
+                        if (activeAppId) onCloseInlineApp?.();
+                        setAppsOpen(false);
+                      }}
+                      className={cn(
+                        "flex flex-col items-center gap-1.5 rounded-lg py-3 px-1 text-center transition-colors hover:bg-muted",
+                        isActive(app.href) && "bg-muted"
+                      )}
+                    >
+                      <Icon className="w-6 h-6 text-muted-foreground" />
+                      <span className="text-xs truncate max-w-full">{app.label}</span>
+                    </Link>
+                  );
+                })}
+                {sidebarApps.map((app) => {
+                  const AppIcon = iconForName(app.icon);
+                  return (
+                    <button
+                      key={app.id}
+                      type="button"
+                      role="menuitem"
+                      onClick={() => {
+                        setAppsOpen(false);
+                        if (activeAppId === app.id) {
+                          onCloseInlineApp?.();
+                        } else if (app.openMode === "tab") {
+                          window.open(app.url, "_blank", "noopener,noreferrer");
+                        } else {
+                          onInlineApp?.(app.id, app.url, app.name);
+                        }
+                      }}
+                      className={cn(
+                        "flex flex-col items-center gap-1.5 rounded-lg py-3 px-1 text-center transition-colors hover:bg-muted",
+                        activeAppId === app.id && "bg-muted"
+                      )}
+                    >
+                      {AppIcon ? <AppIcon className="w-6 h-6 text-muted-foreground" /> : null}
+                      <span className="text-xs truncate max-w-full">{app.name}</span>
+                    </button>
+                  );
+                })}
+              </div>
+              {onManageApps && (
+                <button
+                  type="button"
+                  role="menuitem"
+                  onClick={() => {
+                    setAppsOpen(false);
+                    onManageApps();
+                  }}
+                  className="mt-2 w-full rounded-lg py-2 text-sm text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
+                >
+                  {t("add_app")}
+                </button>
+              )}
+            </div>
+          )}
+        </div>
+
+        <AccountSwitcher
+          variant="header"
+          className="ms-1"
+          onSelectAllInboxes={onSelectAllInboxes}
+          allInboxesSelected={allInboxesSelected}
+        />
+      </div>
+    </header>
+  );
+}
diff --git a/components/layout/navigation-rail.tsx b/components/layout/navigation-rail.tsx
index dd8940a5a..66cabd71d 100644
--- a/components/layout/navigation-rail.tsx
+++ b/components/layout/navigation-rail.tsx
@@ -213,6 +213,7 @@ export function NavigationRail({
   const supportsFiles = client?.supportsFiles() ?? false;
   const supportsContacts = client?.supportsContacts() ?? false;
   const showRailAccountList = useSettingsStore((s) => s.showRailAccountList);
+  const mountainView = useSettingsStore((s) => s.interfaceLayout === 'mountain-view');
   const sidebarAppsEnabled = usePolicyStore((s) => s.isFeatureEnabled('sidebarAppsEnabled'));
   const filesEnabled = usePolicyStore((s) => s.isFeatureEnabled('filesEnabled'));
   const contactsEnabled = usePolicyStore((s) => s.isFeatureEnabled('contactsEnabled'));
@@ -338,7 +339,8 @@ export function NavigationRail({
       return activeItemId === itemId;
     }
     if (href === "/") {
-      return pathname === "/" || pathname === "";
+      // Mountain View's bottom bar marks the mail tab on mail routes too.
+      return pathname === "/" || pathname === "" || (mountainView && pathname.startsWith("/mail"));
     }
     return pathname.startsWith(href);
   };
@@ -360,7 +362,12 @@ export function NavigationRail({
   if (orientation === "horizontal") {
     return (
       <nav
-        className={cn("flex items-center bg-background border-t border-border shrink-0 overflow-x-auto mobile-scroll-hidden pb-[calc(env(safe-area-inset-bottom)/2)]", className)}
+        data-mobile-navigation=""
+        className={cn(
+          "flex items-center bg-background border-t border-border shrink-0 overflow-x-auto mobile-scroll-hidden pb-[calc(env(safe-area-inset-bottom)/2)]",
+          mountainView && "min-h-16 border-t-0 bg-secondary shadow-[0_-1px_3px_rgb(0_0_0/0.08)]",
+          className
+        )}
         role="navigation"
         aria-label={t("nav_label")}
       >
@@ -381,14 +388,17 @@ export function NavigationRail({
               )}
               aria-current={isActive ? "page" : undefined}
             >
-              <div className="relative">
+              <div className={cn(
+                "relative",
+                mountainView && isActive && "min-w-14 rounded-full bg-primary/15 px-4 py-[3px]"
+              )}>
                 <Icon className="w-5 h-5" />
                 {item.badge != null && item.badge > 0 && (
                   <span className="absolute -top-1.5 -right-2.5 flex items-center justify-center min-w-[16px] h-4 text-[10px] font-bold rounded-full bg-red-500 text-white px-1">
                     {item.badge > 99 ? "99+" : item.badge}
                   </span>
                 )}
-                {isActive && (
+                {isActive && !mountainView && (
                   <span className="absolute -bottom-1 left-1/2 -translate-x-1/2 w-4 h-0.5 rounded-full bg-primary" />
                 )}
               </div>
diff --git a/components/layout/sidebar.tsx b/components/layout/sidebar.tsx
index df6c38f90..7de0d1eb7 100644
--- a/components/layout/sidebar.tsx
+++ b/components/layout/sidebar.tsx
@@ -17,6 +17,7 @@ import {
   ChevronsRight,
   ChevronRight,
   ChevronDown,
+  ChevronUp,
   Folder,
   FolderOpen,
   User,
@@ -31,6 +32,7 @@ import {
   Loader2,
   AlertTriangle,
   NotebookPen,
+  PenSquare,
   CalendarClock,
   BellOff,
   Mails,
@@ -80,6 +82,12 @@ interface SidebarProps {
   onMailboxSelect?: (mailboxId: string) => void;
   onTagSelect?: (keywordId: string | null) => void;
   onCompose?: () => void;
+  /**
+   * Mountain View, desktop only: the rail grows a Compose pill at the top and
+   * drops its own header, because the global top bar already carries the
+   * collapse control and the account switcher.
+   */
+  mvShell?: boolean;
   onSidebarClose?: () => void;
   onUnreadFilterClick?: (mailboxId: string) => void;
   onMarkFolderRead?: (mailboxId: string) => void;
@@ -107,6 +115,8 @@ interface SidebarProps {
   /** Gated All mail / Unread / Starred entries in the "Unified Mailbox" section. */
   showCrossUnread?: boolean;
   showCrossStarred?: boolean;
+  /** Mountain View: open Starred from its own row under the Inbox. */
+  onOpenStarred?: () => void;
   showCrossAll?: boolean;
   /** Unread total across all cross-view folders (badge for unread/all). */
   crossUnreadCount?: number;
@@ -320,6 +330,7 @@ function SidebarRow({
       {...(dropHandlers || {})}
       onContextMenu={onContextMenu}
       data-testid="folder-row"
+      data-mv-nav-row=""
       data-folder-role={testRole ?? undefined}
       data-folder-name={testName ?? undefined}
       data-mailbox-id={testMailboxId ?? undefined}
@@ -815,7 +826,7 @@ export function Sidebar({
   selectedKeyword = null,
   onMailboxSelect,
   onTagSelect,
-  onCompose: _onCompose,
+  onCompose,
   onSidebarClose,
   onUnreadFilterClick,
   onMarkFolderRead,
@@ -836,6 +847,7 @@ export function Sidebar({
   crossAccountActive = false,
   showCrossUnread = false,
   showCrossStarred = false,
+  onOpenStarred,
   showCrossAll = false,
   crossUnreadCount = 0,
   className,
@@ -843,13 +855,23 @@ export function Sidebar({
   accountMailboxes,
   viewingAccountId = null,
   onAccountMailboxSelect,
+  mvShell = false,
 }: SidebarProps) {
   const router = useRouter();
-  const { sidebarCollapsed: isCollapsed, toggleSidebarCollapsed } = useUIStore();
+  const { sidebarCollapsed, toggleSidebarCollapsed } = useUIStore();
+  // Mountain View's collapsed rail is a peek, not a commitment: putting the pointer on
+  // it slides the full list back out over the message list and takes it away
+  // again on leaving, so a folder two clicks deep costs no clicks at all. It
+  // floats rather than widening the column, or every hover would reflow the
+  // list behind it.
+  const [railHovered, setRailHovered] = useState(false);
+  const hoverExpanded = mvShell && sidebarCollapsed && railHovered;
+  const isCollapsed = sidebarCollapsed && !hoverExpanded;
   const { primaryIdentity: _primaryIdentity, activeAccountId } = useAuthStore();
   const [expandedFolders, setExpandedFolders] = useState<Set<string>>(new Set());
   const [expandedTags, setExpandedTags] = useState<Set<string>>(new Set());
   const [showAllTags, setShowAllTags] = useState(false);
+  const [moreExpanded, setMoreExpanded] = useState(false);
   const [foldersExpanded, setFoldersExpanded] = useState(() => {
     try {
       const stored = localStorage.getItem('sidebarFoldersExpanded');
@@ -1011,6 +1033,22 @@ export function Sidebar({
   const ownTree = mailboxTree.filter(n => !n.id.startsWith('shared-account-') && !isServerScheduledNode(n));
   const sharedAccounts = mailboxTree.filter(n => n.id.startsWith('shared-account-'));
 
+  // Mountain View's navigation is one flat list of the few places mail
+  // actually goes, with everything else - the folders you made, the shared
+  // ones, the labels - behind a single "More". The "Folders" and "Tags"
+  // headings say the same thing the icons already do, so the first heading
+  // goes and the rest move below the expander. The collapsed rail is left as
+  // it is: it shows icons only, and hiding half of them behind a word would
+  // leave a control with no room to put it.
+  const mvFlat = mvShell && !isCollapsed;
+  const isPrimaryFolder = (node: MailboxNode) =>
+    node.role === 'inbox' || node.role === 'sent' || node.role === 'drafts';
+  const primaryTree = mvFlat ? ownTree.filter(isPrimaryFolder) : ownTree;
+  const secondaryTree = mvFlat ? ownTree.filter((node) => !isPrimaryFolder(node)) : [];
+  // Everything under "More" is hidden together, so one flag covers the extra
+  // folders, the shared accounts and the labels.
+  const showSecondary = !mvFlat || moreExpanded;
+
   // With nesting off every tag is its own root, so the same rows render through
   // one path whether or not the ids describe a hierarchy.
   const tagTree: KeywordNode[] = nestedTags
@@ -1213,17 +1251,24 @@ export function Sidebar({
 
   return (
     <div
+      onMouseEnter={mvShell && sidebarCollapsed ? () => setRailHovered(true) : undefined}
+      onMouseLeave={mvShell && sidebarCollapsed ? () => setRailHovered(false) : undefined}
+      data-mv-rail-peek={hoverExpanded ? "" : undefined}
       className={cn(
         "relative flex flex-col h-full border-e transition-all duration-300 overflow-hidden",
         "bg-secondary border-border",
         "max-lg:w-full",
         isCollapsed ? "lg:w-12" : "lg:w-full",
+        // Floats out of the rail's own column rather than widening it, so the
+        // message list underneath never moves while the pointer passes over.
+        // Width comes from --mv-rail-peek-w, keyed on data-mv-rail-peek.
+        hoverExpanded && "lg:absolute lg:inset-y-0 lg:start-0 lg:z-40 lg:shadow-xl",
         className
       )}
     >
       {/* Header - hidden in the Pro shell, which owns its own chrome and
           would otherwise render an empty strip (no collapse, no switcher). */}
-      {!isEmbedded && (
+      {!isEmbedded && !mvShell && (
         // Border lives on the wrapper (outside the h-14 box) so the bar's total
         // height matches the search/reply toolbars, which border-b their wrapper too.
         <div className="border-b border-border">
@@ -1255,6 +1300,26 @@ export function Sidebar({
         </div>
       )}
 
+      {mvShell && onCompose && (
+        <div className={cn("pt-2 pb-3", isCollapsed ? "px-2" : "px-3")}>
+          <button
+            type="button"
+            onClick={onCompose}
+            data-mv-compose=""
+            data-tour="compose-button"
+            className={cn(
+              "flex items-center bg-primary text-primary-foreground shadow-sm hover:shadow-md transition-shadow",
+              isCollapsed ? "w-14 justify-center" : "gap-3 ps-4 pe-6"
+            )}
+            title={t("compose_hint")}
+            aria-label={t("compose")}
+          >
+            <PenSquare className="w-5 h-5 flex-shrink-0" />
+            {!isCollapsed && <span className="text-sm font-medium">{t("compose")}</span>}
+          </button>
+        </div>
+      )}
+
       {!isCollapsed && <DemoBanner />}
       {!isCollapsed && <VacationBanner />}
 
@@ -1382,16 +1447,18 @@ export function Sidebar({
           })
         ) : (
           <div onContextMenu={handleFoldersHeaderContextMenu}>
-            <SidebarSectionHeader
-              label={t("folders")}
-              expanded={foldersExpanded}
-              onToggle={toggleFolders}
-              onSettings={openFolderSettings}
-              settingsTitle={t('settings')}
-              isCollapsed={isCollapsed}
-              first={!showUnified}
-            />
-            {((foldersExpanded && !isCollapsed) || isCollapsed) && (
+            {!mvFlat && (
+              <SidebarSectionHeader
+                label={t("folders")}
+                expanded={foldersExpanded}
+                onToggle={toggleFolders}
+                onSettings={openFolderSettings}
+                settingsTitle={t('settings')}
+                isCollapsed={isCollapsed}
+                first={!showUnified}
+              />
+            )}
+            {(mvFlat || (foldersExpanded && !isCollapsed) || isCollapsed) && (
               <>
                 {mailboxes.length === 0 ? (
                   <div className="px-4 py-2 text-sm text-muted-foreground">
@@ -1399,7 +1466,7 @@ export function Sidebar({
                   </div>
                 ) : (
                   <>
-                    {ownTree.map((node) => (
+                    {primaryTree.map((node) => (
                       <Fragment key={node.id}>
                         <MailboxTreeItem
                           node={node}
@@ -1413,9 +1480,48 @@ export function Sidebar({
                           onContextMenu={handleMailboxContextMenu}
                         />
                         {node.role === 'drafts' && renderScheduledRow('scheduled')}
+                        {/* Mountain View lists Starred right under the Inbox. */}
+                        {mvFlat && node.role === 'inbox' && onOpenStarred && (
+                          <SidebarRow
+                            icon={<Star className="w-4 h-4 text-muted-foreground" />}
+                            label={t("mailboxes.starred")}
+                            testName="mv-starred"
+                            depth={0}
+                            isSelected={selectedMailbox === CROSS_VIEW_IDS.starred}
+                            onClick={onOpenStarred}
+                            isCollapsed={false}
+                          />
+                        )}
                       </Fragment>
                     ))}
-                    {!ownTree.some((node) => node.role === 'drafts') && renderScheduledRow('scheduled')}
+                    {!primaryTree.some((node) => node.role === 'drafts') && renderScheduledRow('scheduled')}
+                    {mvFlat && (
+                      <SidebarRow
+                        icon={moreExpanded
+                          ? <ChevronUp className="w-4 h-4 text-muted-foreground" />
+                          : <ChevronDown className="w-4 h-4 text-muted-foreground" />}
+                        label={moreExpanded ? t("show_fewer") : t("show_more")}
+                        testName="mv-more"
+                        depth={0}
+                        isSelected={false}
+                        onClick={() => setMoreExpanded((prev) => !prev)}
+                        isCollapsed={false}
+                      />
+                    )}
+                    {mvFlat && moreExpanded && secondaryTree.map((node) => (
+                      <MailboxTreeItem
+                        key={node.id}
+                        node={node}
+                        selectedMailbox={selectedKeyword ? "" : selectedMailbox}
+                        expandedFolders={expandedFolders}
+                        onMailboxSelect={onMailboxSelect}
+                        onToggleExpand={handleToggleExpand}
+                        isCollapsed={isCollapsed}
+                        onUnreadFilterClick={onUnreadFilterClick}
+                        colorful={colorfulSidebarIcons}
+                        onContextMenu={handleMailboxContextMenu}
+                      />
+                    ))}
                   </>
                 )}
               </>
@@ -1423,7 +1529,7 @@ export function Sidebar({
           </div>
         )}
 
-        {!useMultiAccount && sharedAccounts.length > 0 && (
+        {!useMultiAccount && showSecondary && sharedAccounts.length > 0 && (
           <div>
             <SidebarSectionHeader
               label={t("shared")}
@@ -1482,7 +1588,7 @@ export function Sidebar({
           </div>
         )}
 
-        {emailKeywords.length > 0 && (
+        {showSecondary && emailKeywords.length > 0 && (
           <div data-tour="keyword-tags">
             <SidebarSectionHeader
               label={t("tags")}
diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index b51b830d9..78687a470 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -5,6 +5,7 @@ import { usePathname } from "next/navigation";
 import { useTranslations } from "next-intl";
 import { Sidebar } from "@/components/layout/sidebar";
 import { EmailList } from "@/components/email/email-list";
+import { MvComposeWindow } from "@/components/email/mv-compose-window";
 import { MessageListTabs } from "@/components/email/message-list-tabs";
 import dynamic from "next/dynamic";
 import type { ComposerDraftData } from "@/components/email/email-composer";
@@ -25,7 +26,7 @@ const EmailComposer = dynamic(
 import { ProtocolAccountPicker } from "@/components/protocol/protocol-account-picker";
 import { ThreadConversationView } from "@/components/email/thread-conversation-view";
 import { MobileHeader } from "@/components/layout/mobile-header";
-import { ThreadGroup, Email, Mailbox, type StateChange, isUnifiedMailboxId, UNIFIED_ROLE_BY_ID, CROSS_VIEW_BY_ID, isCrossViewId } from "@/lib/jmap/types";
+import { ThreadGroup, Email, Mailbox, type StateChange, isUnifiedMailboxId, UNIFIED_MAILBOX_IDS, UNIFIED_ROLE_BY_ID, CROSS_VIEW_BY_ID, CROSS_VIEW_IDS, isCrossViewId } from "@/lib/jmap/types";
 import { useAccountStore, waitForConnectedAccount } from "@/stores/account-store";
 import { usePolicyStore } from "@/stores/policy-store";
 import type { UnifiedAccountClient } from "@/lib/unified-mailbox";
@@ -42,13 +43,14 @@ import { ShareNotificationToaster } from "@/components/layout/share-notification
 import { CalendarEventNotificationToaster } from "@/components/layout/calendar-event-notification-toaster";
 import { useAuthStore, redirectToLogin, saveRedirectAfterLogin } from '@/stores/auth-store';
 import { useSettingsStore } from "@/stores/settings-store";
+import { useEffectiveMailLayout } from "@/hooks/use-effective-mail-layout";
 import { useContactStore } from "@/stores/contact-store";
 import { useIdentityStore } from "@/stores/identity-store";
 import { useUIStore } from "@/stores/ui-store";
 import { useDeviceDetection } from "@/hooks/use-media-query";
 import { usePaneSize } from "@/hooks/use-pane-size";
 import { usePaneId } from "@/hooks/use-pane-context";
-import { useKeyboardShortcuts } from "@/hooks/use-keyboard-shortcuts";
+import { useKeyboardShortcuts, type GoToMailboxTarget } from "@/hooks/use-keyboard-shortcuts";
 import { useRefreshGesture } from "@/hooks/use-refresh-gesture";
 import { useConfirmDialog } from "@/hooks/use-confirm-dialog";
 import { usePromptDialog } from "@/hooks/use-prompt-dialog";
@@ -70,14 +72,17 @@ import { ConfirmDialog } from "@/components/ui/confirm-dialog";
 import { PromptDialog } from "@/components/ui/prompt-dialog";
 import { TotpReauthDialog } from "@/components/totp-reauth-dialog";
 import { DragDropProvider } from "@/contexts/drag-drop-context";
-import { isFilterEmpty, activeFilterCount } from "@/lib/jmap/search-utils";
+import { isFilterEmpty, activeFilterCount, DEFAULT_SEARCH_FILTERS } from "@/lib/jmap/search-utils";
 import { SearchBox, type ContactSearchField } from "@/components/search/search-box";
+import { FilterPanelHost } from "@/components/search/filter-panel-host";
 import type { ContactSuggestion } from "@/lib/search-suggestions";
 import type { Attachment } from "@/lib/jmap/types";
 import { peekListAttachments, requestListAttachments, type ListAttachmentSource, type LoadListAttachments } from "@/lib/list-attachments";
 import { useSearchHistoryStore } from "@/stores/search-history-store";
 import { WelcomeBanner } from "@/components/ui/welcome-banner";
 import { NavigationRail } from "@/components/layout/navigation-rail";
+import { MvTopBar } from "@/components/layout/mv-top-bar";
+import { MvListToolbar } from "@/components/email/mv-list-toolbar";
 import { SidebarAppsModal } from "@/components/layout/sidebar-apps-modal";
 import { InlineAppView } from "@/components/layout/inline-app-view";
 import { useSidebarApps } from "@/hooks/use-sidebar-apps";
@@ -166,7 +171,8 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
   const tCommon = useTranslations('common');
   const tQuote = useTranslations('quote_header');
   const { appName } = useConfig();
-  const mailLayout = useSettingsStore((state) => state.mailLayout);
+  const mailLayout = useEffectiveMailLayout();
+  const interfaceLayout = useSettingsStore((state) => state.interfaceLayout);
   // Phones present search full-screen from the header field rather than
   // giving it a permanent second bar under the header.
   const [mobileSearchOpen, setMobileSearchOpen] = useState(false);
@@ -349,6 +355,18 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
   // Mobile/tablet responsive hooks
   const { isMobile, isTablet } = useDeviceDetection();
   const isEmbedded = useIsEmbedded();
+  /**
+   * Mountain View's list cursor. `j` / `k` there move a highlight without
+   * opening the conversation, marking it read or changing the URL - only
+   * Enter / `o` / a click do that. The app otherwise treats "selected" and
+   * "open" as the same thing, so Mountain View keeps the selection (every
+   * action already targets it) and records that it is only a cursor.
+   */
+  const [cursorOnly, setCursorOnly] = useState(false);
+  // Desktop lifts search into a global header. Mobile keeps its native
+  // one-pane flow, with Mountain View's own app chrome.
+  const mvShell = interfaceLayout === 'mountain-view' && !isMobile && !isTablet && !isEmbedded;
+  const mvMobile = interfaceLayout === 'mountain-view' && isMobile && !isEmbedded;
   // Pane hosting (Pro shell). When this app renders inside a Pro pane, the
   // pane publishes its width and id; `isMobile` above is then pane-based,
   // and layout that would use viewport-fixed positioning must scope itself
@@ -532,6 +550,17 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     unifiedCrossAccountGate &&
     accounts.filter((a) => a.isConnected).length > 1;
 
+  // Mountain View's account popover offers the merged inbox above the addresses it
+  // merges. Offering it when it cannot be built would give a row that selects
+  // an empty list, so it appears on exactly the terms the sidebar's own
+  // unified section does.
+  const allInboxesReachable = enableUnifiedMailbox && crossAccountActive;
+  const allInboxesSelected = selectedMailbox === UNIFIED_MAILBOX_IDS.inbox;
+
+  // The node the Mountain View top bar renders under its search field; the filter
+  // panel is portalled into it so it hangs off the control that opens it.
+  const [filterAnchor, setFilterAnchor] = useState<HTMLDivElement | null>(null);
+
   // Builds the populated UnifiedAccountClient[] used by the unified-view
   // effects and one-shot actions in this page. Reads the settings at call time
   // so the latest toggle values are always honored. When the cross-account
@@ -687,7 +716,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
 
   useBrowserNavigation({
     mailboxId: selectedMailbox,
-    emailId: selectedEmail?.id ?? null,
+    emailId: mvShell && cursorOnly ? null : (selectedEmail?.id ?? null),
     threadId: conversationThread?.threadId ?? null,
     composerOpen: showComposer,
     sidebarOpen,
@@ -703,7 +732,8 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       const currentIndex = selectedEmail ? activeEmails.findIndex(e => e.id === selectedEmail.id) : -1;
       const nextIndex = currentIndex < activeEmails.length - 1 ? currentIndex + 1 : currentIndex;
       if (nextIndex >= 0 && nextIndex < activeEmails.length) {
-        handleEmailSelect(activeEmails[nextIndex]);
+        void handleEmailSelect(activeEmails[nextIndex]);
+        if (mvShell) setCursorOnly(true);
       }
     },
     onPreviousEmail: () => {
@@ -711,13 +741,17 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       const currentIndex = selectedEmail ? activeEmails.findIndex(e => e.id === selectedEmail.id) : activeEmails.length;
       const prevIndex = currentIndex > 0 ? currentIndex - 1 : 0;
       if (prevIndex >= 0 && prevIndex < activeEmails.length) {
-        handleEmailSelect(activeEmails[prevIndex]);
+        void handleEmailSelect(activeEmails[prevIndex]);
+        if (mvShell) setCursorOnly(true);
       }
     },
     onOpenEmail: () => {
-      // Email is already opened when selected
+      // Outside Mountain View the email is already open by virtue of being
+      // selected; under it this is the step that promotes cursor to open.
+      setCursorOnly(false);
     },
     onCloseEmail: () => {
+      setCursorOnly(false);
       selectEmail(null);
       if (isMobile) {
         setActiveView("list");
@@ -868,6 +902,38 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     onDeselectAll: () => {
       clearSelection();
     },
+    // `x` under Mountain View: put the focused conversation in or out of the
+    // selection. Only reachable there, where `x` is handed over from thread
+    // expansion.
+    onToggleSelection: () => {
+      if (isScheduledView || !selectedEmail) return;
+      toggleEmailSelection(selectedEmail.id);
+    },
+    // Mountain View's `g` sequences. `g s` goes to the "All starred" view when
+    // the user has one - a list you arrive at and leave, like the other `g`
+    // destinations. Without it there is no starred destination here, and the
+    // fallback is the advanced-search star toggle: it shows the same messages,
+    // but as a search you then have to clear. All mail uses the folder the
+    // account nominated in Layout settings, falling back to its Archive.
+    onGoToMailbox: (target: GoToMailboxTarget) => {
+      if (isScheduledView && target !== 'inbox') return;
+      if (target === 'starred') {
+        goToStarred();
+        return;
+      }
+      const roleFor = { inbox: 'inbox', sent: 'sent', drafts: 'drafts' } as const;
+      if (target === 'all') {
+        const configured = viewingAccountId
+          ? useSettingsStore.getState().allMailFolderIds[viewingAccountId]
+          : undefined;
+        const allMailId = (typeof configured === 'string' ? configured : undefined)
+          ?? mailboxes.find((mb) => mb.role === 'archive')?.id;
+        if (allMailId) void handleMailboxSelect(allMailId);
+        return;
+      }
+      const mailbox = mailboxes.find((mb) => mb.role === roleFor[target]);
+      if (mailbox) void handleMailboxSelect(mailbox.id);
+    },
     // `x` in the help modal: expand/collapse the selected email's thread. Same
     // steps as EmailList.handleToggleThreadExpansion - expanding pulls the
     // thread's messages and marks them read, collapsing only toggles. (#683)
@@ -885,7 +951,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       }
     },
   // eslint-disable-next-line react-hooks/exhaustive-deps
-  }), [activeEmails, selectedEmail, client, selectedMailbox, isMobile, isTablet, selectedEmailIds, mailboxes, isScheduledView]);
+  }), [activeEmails, selectedEmail, client, selectedMailbox, isMobile, isTablet, selectedEmailIds, mailboxes, isScheduledView, mvShell, showCrossStarred]);
 
   // Initialize keyboard shortcuts
   useKeyboardShortcuts({
@@ -893,6 +959,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     emails: activeEmails,
     selectedEmailId: selectedEmail?.id,
     selectionCount: selectedEmailIds.size,
+    mountainViewKeys: mvShell,
     handlers: keyboardHandlers,
   });
 
@@ -1677,6 +1744,12 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       return;
     }
 
+    // A Mountain View cursor is not a read receipt: the mail is only marked once it is
+    // actually opened.
+    if (mvShell && cursorOnly) {
+      return;
+    }
+
     // Get current setting value
     const markAsReadDelay = useSettingsStore.getState().markAsReadDelay;
     debug.log('email', '[Mark as Read] Delay setting:', markAsReadDelay, 'ms for email:', selectedEmail.id);
@@ -1707,7 +1780,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       }
     };
     // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [selectedEmail?.id, isScheduledView]);
+  }, [selectedEmail?.id, isScheduledView, mvShell, cursorOnly]);
 
   // Handle new email notifications - play sound
   useEffect(() => {
@@ -3121,6 +3194,18 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     }
   };
 
+  // Starred for Mountain View: the "All starred" view when the user has one, otherwise
+  // the advanced-search star toggle, which shows the same messages as a
+  // search. Used by `g s` and by Mountain View's Starred row.
+  const goToStarred = () => {
+    if (showCrossStarred) {
+      void handleMailboxSelect(CROSS_VIEW_IDS.starred);
+      return;
+    }
+    setSearchFilters({ ...DEFAULT_SEARCH_FILTERS, isStarred: true });
+    void handleAdvancedSearch();
+  };
+
   const handleAdvancedSearch = async () => {
     if (!client) return;
     await advancedSearch(client);
@@ -3468,7 +3553,11 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       })();
   const isFocusedMailLayout = mailLayout === 'focus';
   const isHorizontalMailLayout = mailLayout === 'horizontal' && !isMobile && !isTablet;
-  const hasViewerContent = showComposer || Boolean(conversationThread) || Boolean(selectedEmail);
+  // Under Mountain View on desktop the composer floats over the list in a
+  // docked window instead of taking the reading pane.
+  const floatingComposer = mvShell && showComposer && !isEmbedded;
+  const hasViewerContent = (showComposer && !floatingComposer) || Boolean(conversationThread)
+    || Boolean(selectedEmail && !(mvShell && cursorOnly));
   const shouldCollapseListPane = (isTablet && !tabletListVisible && !readingPaneEmpty) || (!isMobile && isFocusedMailLayout && hasViewerContent);
   const shouldHideViewerPane = !isMobile && !hasViewerContent && isFocusedMailLayout;
   const shouldHideHorizontalViewerPane = isHorizontalMailLayout && !hasViewerContent;
@@ -3478,6 +3567,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     email: { id: string } & Partial<Pick<Email, 'sourceClientAccountId' | 'sourceAccountId'>>,
   ) => {
     if (!client || !email) return;
+    setCursorOnly(false);
 
     // If composing, suspend the composer (unmount will trigger onSaveState)
     if (showComposer) {
@@ -3695,6 +3785,87 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     </button>
   );
 
+  // The composer, rendered in the reading pane - or, under Mountain View on
+  // desktop, in a window docked over the list (see MvComposeWindow).
+  const composerNode = (
+    <ErrorBoundary
+      fallback={ComposerErrorFallback}
+      onReset={() => {
+        setShowComposer(false);
+        setComposerMode('compose');
+        setComposerQuoteHeader(null);
+      }}
+    >
+      <EmailComposer
+        key={composerSessionId}
+        mode={pendingDraft?.mode ?? composerMode}
+        composeFromAccountEmail={resolveComposeAccountEmail(
+          mailboxes,
+          selectedMailbox,
+          useAccountStore
+            .getState()
+            .getAccountById(viewingAccountId ?? activeAccountId ?? '')?.email,
+        )}
+        replyTo={pendingDraft !== null ? pendingDraft.replyTo : (selectedEmail ? {
+          from: selectedEmail.from,
+          replyToAddresses: selectedEmail.replyTo,
+          to: selectedEmail.to,
+          cc: selectedEmail.cc,
+          bcc: selectedEmail.bcc,
+          subject: selectedEmail.subject,
+          ...getQuoteBodies(selectedEmail),
+          receivedAt: selectedEmail.receivedAt,
+          // The login that holds the message, so the reply
+          // defaults to that account's identity (#1104).
+          accountId: selectedEmail.sourceClientAccountId ?? viewingAccountId ?? undefined,
+          attachments: selectedEmail.attachments,
+          messageId: selectedEmail.messageId,
+          inReplyTo: selectedEmail.inReplyTo,
+          references: selectedEmail.references,
+          quoteHeaderHtml: composerQuoteHeader?.html,
+          quoteHeaderText: composerQuoteHeader?.text,
+          quoteWrapInBlockquote: composerQuoteHeader?.wrapInBlockquote,
+        } : undefined)}
+        initialDraftText={composerDraftText}
+        initialData={pendingDraft}
+        onSaveState={(data) => {
+          if (suppressComposerStateSaveSessionRef.current === composerSessionId) {
+            suppressComposerStateSaveSessionRef.current = null;
+            return;
+          }
+          setPendingDraft(data);
+        }}
+        onSend={async (data) => {
+          await handleEmailSend(data);
+          setPendingDraft(null);
+        }}
+        onScheduledSendCreated={async () => {
+          if (client) {
+            await refreshScheduledMetadata(client);
+            if (isScheduledView) await fetchScheduledEmails(client);
+          }
+          setShowComposer(false);
+          setPendingDraft(null);
+        }}
+        onClose={() => {
+          setShowComposer(false);
+          setComposerMode('compose');
+          setComposerDraftText("");
+          setPendingDraft(null);
+          setComposerQuoteHeader(null);
+          if (isMobile) {
+            setActiveView('list');
+          }
+        }}
+        requestCloseRef={composerRequestCloseRef}
+        onDiscardDraft={(draftId) => {
+          handleDiscardDraft(draftId);
+          setPendingDraft(null);
+        }}
+      />
+    </ErrorBoundary>
+  );
+
   if (!isAuthenticated) {
     return null;
   }
@@ -3717,9 +3888,33 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
             <span>{tCommon('reconnecting')}</span>
           </div>
         )}
+        {mvShell && !fullscreenReading && (
+          <MvTopBar
+            searchQuery={searchQuery}
+            onSearchQueryChange={setSearchQuery}
+            onSearchSubmit={handleSearch}
+            onSearchClear={handleClearSearch}
+            onSelectContact={handleSelectContactSuggestion}
+            onToggleFilters={toggleAdvancedSearch}
+            filtersOpen={isAdvancedSearchOpen}
+            activeFilterCount={activeFilterCount(searchFilters)}
+            searchDisabled={isScheduledView}
+            onShowShortcuts={() => setShowShortcutsModal(true)}
+            onManageApps={handleManageApps}
+            onInlineApp={handleInlineApp}
+            onCloseInlineApp={closeInlineApp}
+            activeAppId={inlineApp?.id ?? null}
+            onSelectAllInboxes={
+              allInboxesReachable ? () => handleMailboxSelect(UNIFIED_MAILBOX_IDS.inbox) : undefined
+            }
+            allInboxesSelected={allInboxesSelected}
+            onFilterAnchorChange={setFilterAnchor}
+          />
+        )}
         <div className="flex flex-1 overflow-hidden">
-        {/* Desktop Navigation Rail (hidden when embedded inside Pro shell) */}
-        {!isMobile && !isTablet && !isEmbedded && (
+        {/* Desktop Navigation Rail (hidden when embedded inside Pro shell, and
+            under Mountain View, whose header carries the app grid instead) */}
+        {!isMobile && !isTablet && !isEmbedded && !mvShell && (
           <div className="w-14 bg-secondary flex flex-col flex-shrink-0" style={{ borderRight: '1px solid rgba(128, 128, 128, 0.3)' }}>
             <NavigationRail
               collapsed
@@ -3793,7 +3988,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
             inlineApp && "hidden",
             fullscreenReading && "hidden"
           )}
-          style={!isMobile && !isTablet ? { width: sidebarCollapsed ? 48 : sidebarWidth } : undefined}
+          style={!isMobile && !isTablet ? { width: sidebarCollapsed ? (mvShell ? 72 : 48) : sidebarWidth } : undefined}
         >
           <ErrorBoundary fallback={SidebarErrorFallback}>
             <Sidebar
@@ -3807,6 +4002,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
               crossAccountActive={crossAccountActive}
               showCrossUnread={showCrossUnread}
               showCrossStarred={showCrossStarred}
+              onOpenStarred={mvShell ? goToStarred : undefined}
               showCrossAll={showCrossAll}
               crossUnreadCount={crossUnreadCount}
               onMailboxSelect={handleMailboxSelect}
@@ -3833,6 +4029,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
                 }
               }}
               onSidebarClose={() => setSidebarOpen(false)}
+              mvShell={mvShell}
               multiAccountMode={isEmbedded}
               accountMailboxes={accountMailboxes}
               viewingAccountId={viewingAccountId}
@@ -3894,6 +4091,10 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
               searchPlaceholder={searchQuery || t('sidebar.search_placeholder_hint')}
               searchActive={!!searchQuery}
               onClearSearch={handleClearSearch}
+              onSelectAllInboxes={
+                allInboxesReachable ? () => handleMailboxSelect(UNIFIED_MAILBOX_IDS.inbox) : undefined
+              }
+              allInboxesSelected={allInboxesSelected}
             />
 
             {/* Search Bar + Inline Advanced Filters. On phones this is not a
@@ -3920,6 +4121,18 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
                   <span className="font-medium truncate">{t('sidebar.search_placeholder_hint')}</span>
                 </div>
               )}
+              {mvShell ? (
+                <MvListToolbar
+                  loadedCount={activeEmails.length}
+                  totalCount={mailboxes.find((mb) => mb.id === selectedMailbox)?.totalEmails}
+                  onRefresh={handleManualRefresh}
+                  isRefreshing={isManualRefreshing}
+                  onMarkFolderRead={selectedMailbox ? () => handleMarkFolderRead(selectedMailbox) : undefined}
+                  onMarkAllFoldersRead={handleMarkAllFoldersRead}
+                  onEmptyFolder={selectedMailbox ? () => void handleEmptyFolderFromContextMenu(selectedMailbox) : undefined}
+                  disabled={isScheduledView}
+                />
+              ) : (
               <div className="px-3 h-14 flex items-center">
                 <div className="flex items-center gap-1.5 w-full">
                   {/* Select / Select All toggle */}
@@ -4004,10 +4217,13 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
                   </button>
                 </div>
               </div>
+              )}
 
-              {/* Filter Area */}
+              {/* Filter Area. Under Mountain View the button that opens this
+                  lives in the global top bar, so the panel drops from the
+                  search field there rather than from the list header. */}
               {isAdvancedSearchOpen && (
-                <div className="px-3 pb-3 space-y-2.5 animate-in slide-in-from-top-1 fade-in duration-150">
+                <FilterPanelHost anchor={mvShell ? filterAnchor : null}>
                   {/* Quick toggle filters + clear */}
                   <div className="flex items-center justify-between">
                     <div className="flex items-center gap-2 flex-wrap">
@@ -4188,7 +4404,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
                       </div>
                     </div>
                   )}
-                </div>
+                </FilterPanelHost>
               )}
             </div>
             )}
@@ -4215,6 +4431,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
 
             <ErrorBoundary fallback={EmailListErrorFallback}>
               <EmailList
+                hideBatchToolbar={mvShell}
                 emails={activeEmails}
                 selectedEmailId={selectedEmail?.id}
                 isLoading={activeIsLoading}
@@ -4316,8 +4533,9 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
             </ErrorBoundary>
             </div>
 
-            {/* Floating Compose Button */}
-            <Button
+            {/* Floating Compose Button - on desktop Mountain View puts Compose
+                at the top of the navigation rail instead. */}
+            {!mvShell && <Button
               onClick={() => {
                 startFreshComposerSession();
                 setComposerMode('compose');
@@ -4325,15 +4543,20 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
                 if (isMobile) setActiveView('viewer');
               }}
               className={cn(
-                "absolute z-40 rounded-full shadow-lg",
-                isMobile ? "bottom-4 end-4 h-14 w-14" : "bottom-4 end-4 h-12 w-12"
+                "absolute z-40 shadow-lg",
+                mvMobile
+                  ? "bottom-4 end-4 h-14 gap-3 rounded-2xl px-5"
+                  : isMobile
+                    ? "bottom-4 end-4 h-14 w-14 rounded-full"
+                    : "bottom-4 end-4 h-12 w-12 rounded-full"
               )}
               aria-label={t('sidebar.compose')}
               title={t('sidebar.compose_hint')}
               data-tour="compose-button"
             >
               <PenSquare className={isMobile ? "h-6 w-6" : "h-5 w-5"} />
-            </Button>
+              {mvMobile && <span className="text-sm font-medium">{t('sidebar.compose')}</span>}
+            </Button>}
           </div>
 
           {/* Email list resize handle (desktop only) */}
@@ -4377,84 +4600,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
             {/* Inline Composer - shown in viewer pane.
                 In Pro/embedded mode the composer is hoisted into its own
                 Pro tab (see the effect below), so we never render it inline. */}
-            {(showComposer && !isEmbedded) ? (
-              <ErrorBoundary
-                fallback={ComposerErrorFallback}
-                onReset={() => {
-                  setShowComposer(false);
-                  setComposerMode('compose');
-                  setComposerQuoteHeader(null);
-                }}
-              >
-                <EmailComposer
-                  key={composerSessionId}
-                  mode={pendingDraft?.mode ?? composerMode}
-                  composeFromAccountEmail={resolveComposeAccountEmail(
-                    mailboxes,
-                    selectedMailbox,
-                    useAccountStore
-                      .getState()
-                      .getAccountById(viewingAccountId ?? activeAccountId ?? '')?.email,
-                  )}
-                  replyTo={pendingDraft !== null ? pendingDraft.replyTo : (selectedEmail ? {
-                    from: selectedEmail.from,
-                    replyToAddresses: selectedEmail.replyTo,
-                    to: selectedEmail.to,
-                    cc: selectedEmail.cc,
-                    bcc: selectedEmail.bcc,
-                    subject: selectedEmail.subject,
-                    ...getQuoteBodies(selectedEmail),
-                    receivedAt: selectedEmail.receivedAt,
-                    // The login that holds the message, so the reply
-                    // defaults to that account's identity (#1104).
-                    accountId: selectedEmail.sourceClientAccountId ?? viewingAccountId ?? undefined,
-                    attachments: selectedEmail.attachments,
-                    messageId: selectedEmail.messageId,
-                    inReplyTo: selectedEmail.inReplyTo,
-                    references: selectedEmail.references,
-                    quoteHeaderHtml: composerQuoteHeader?.html,
-                    quoteHeaderText: composerQuoteHeader?.text,
-                    quoteWrapInBlockquote: composerQuoteHeader?.wrapInBlockquote,
-                  } : undefined)}
-                  initialDraftText={composerDraftText}
-                  initialData={pendingDraft}
-                  onSaveState={(data) => {
-                    if (suppressComposerStateSaveSessionRef.current === composerSessionId) {
-                      suppressComposerStateSaveSessionRef.current = null;
-                      return;
-                    }
-                    setPendingDraft(data);
-                  }}
-                  onSend={async (data) => {
-                    await handleEmailSend(data);
-                    setPendingDraft(null);
-                  }}
-                  onScheduledSendCreated={async () => {
-                    if (client) {
-                      await refreshScheduledMetadata(client);
-                      if (isScheduledView) await fetchScheduledEmails(client);
-                    }
-                    setShowComposer(false);
-                    setPendingDraft(null);
-                  }}
-                  onClose={() => {
-                    setShowComposer(false);
-                    setComposerMode('compose');
-                    setComposerDraftText("");
-                    setPendingDraft(null);
-                    setComposerQuoteHeader(null);
-                    if (isMobile) {
-                      setActiveView('list');
-                    }
-                  }}
-                  requestCloseRef={composerRequestCloseRef}
-                  onDiscardDraft={(draftId) => {
-                    handleDiscardDraft(draftId);
-                    setPendingDraft(null);
-                  }}
-                />
-              </ErrorBoundary>
-            ) : (
+            {(showComposer && !isEmbedded && !floatingComposer) ? composerNode : (
             <>
             {/* Pending draft banner */}
             {pendingDraft && (
@@ -4654,6 +4800,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
         <ShareNotificationToaster client={client} />
         <CalendarEventNotificationToaster client={client} />
         <TotpReauthDialog />
+        {floatingComposer && <MvComposeWindow>{composerNode}</MvComposeWindow>}
       </div>
     </DragDropProvider>
   );
diff --git a/components/search/__tests__/filter-panel-host.test.tsx b/components/search/__tests__/filter-panel-host.test.tsx
new file mode 100644
index 000000000..4ccc6ad1c
--- /dev/null
+++ b/components/search/__tests__/filter-panel-host.test.tsx
@@ -0,0 +1,55 @@
+import { render, screen } from '@testing-library/react';
+import { describe, it, expect } from 'vitest';
+import { FilterPanelHost } from '../filter-panel-host';
+
+// Mountain View moves the filter button into the global top bar. The panel
+// follows it there, given an anchor; without one it stays in the flow of the
+// message-list column, which is the default layout's arrangement.
+
+describe('FilterPanelHost', () => {
+  it('renders in place when there is no anchor', () => {
+    const { container } = render(
+      <FilterPanelHost anchor={null}><span>filters</span></FilterPanelHost>
+    );
+
+    expect(container).toContainElement(screen.getByText('filters'));
+    expect(container.querySelector('[data-mv-filter-panel]')).toBeNull();
+  });
+
+  it('lines the panel up with the anchor: same leading edge, same width, just below', () => {
+    const anchor = document.createElement('div');
+    anchor.getBoundingClientRect = () =>
+      ({ left: 165, width: 505, top: 56, bottom: 56, right: 670, height: 0, x: 165, y: 56, toJSON: () => ({}) }) as DOMRect;
+    document.body.appendChild(anchor);
+
+    const { container } = render(
+      <FilterPanelHost anchor={anchor}><span>filters</span></FilterPanelHost>
+    );
+
+    const panel = document.querySelector<HTMLElement>('[data-mv-filter-panel]')!;
+    expect(panel).toContainElement(screen.getByText('filters'));
+    expect(container).not.toContainElement(panel);
+    expect(panel.style.left).toBe('165px');
+    expect(panel.style.width).toBe('505px');
+    expect(Number.parseInt(panel.style.top, 10)).toBeGreaterThanOrEqual(56);
+
+    anchor.remove();
+  });
+
+  it('draws it at the end of <body>, above the sidebar column and not inside the top bar', () => {
+    const anchor = document.createElement('div');
+    document.body.appendChild(anchor);
+
+    render(<FilterPanelHost anchor={anchor}><span>filters</span></FilterPanelHost>);
+
+    const panel = document.querySelector<HTMLElement>('[data-mv-filter-panel]')!;
+    // The sidebar column is z-50 and later in the document than the top bar,
+    // so inside the bar the panel lost that tie and was painted over.
+    expect(anchor).not.toContainElement(panel);
+    expect(panel.parentElement).toBe(document.body);
+    expect(panel.className).toContain('fixed');
+    expect(panel.className).toContain('z-50');
+
+    anchor.remove();
+  });
+});
diff --git a/components/search/filter-panel-host.tsx b/components/search/filter-panel-host.tsx
new file mode 100644
index 000000000..10dbb137e
--- /dev/null
+++ b/components/search/filter-panel-host.tsx
@@ -0,0 +1,83 @@
+"use client";
+
+import { useLayoutEffect, useState, type CSSProperties, type ReactNode } from "react";
+import { createPortal } from "react-dom";
+
+/**
+ * Where the advanced-filter panel is drawn.
+ *
+ * With no anchor it stays where it has always been: in the flow of the
+ * message-list column, directly under the header that carries the filter
+ * button. That is the default layout, and nothing about it changes.
+ *
+ * Mountain View moves the filter button up into the global top bar, next to
+ * the search field. Given the anchor the top bar renders under that field, the
+ * panel drops from it instead: same leading edge, same width, directly
+ * below.
+ *
+ * It is portalled to <body> and positioned from the anchor's box rather than
+ * rendered inside the anchor. Inside the top bar it shared the root stacking
+ * context with the sidebar column, which carries the same z-index and comes
+ * later in the document, so the sidebar painted over the panel's leading half.
+ * At the end of <body> it wins that tie, and it still loses to any dialog
+ * opened afterwards, which is the order one wants.
+ */
+export function FilterPanelHost({
+  anchor,
+  children,
+}: {
+  anchor: HTMLElement | null;
+  children: ReactNode;
+}) {
+  const box = useAnchorBox(anchor);
+
+  const panel = (
+    <div className="px-3 pb-3 space-y-2.5 animate-in slide-in-from-top-1 fade-in duration-150">
+      {children}
+    </div>
+  );
+
+  if (!anchor) return panel;
+  if (!box) return null;
+
+  return createPortal(
+    <div
+      data-mv-filter-panel=""
+      style={box}
+      className="fixed z-50 max-h-[calc(100dvh-5rem)] overflow-y-auto rounded-lg border border-border bg-popover pt-3 shadow-xl"
+    >
+      {panel}
+    </div>,
+    document.body
+  );
+}
+
+/** The anchor's leading edge, width and bottom, kept current as the bar resizes. */
+function useAnchorBox(anchor: HTMLElement | null): CSSProperties | null {
+  const [box, setBox] = useState<CSSProperties | null>(null);
+
+  useLayoutEffect(() => {
+    if (!anchor) {
+      setBox(null);
+      return;
+    }
+    const measure = () => {
+      const rect = anchor.getBoundingClientRect();
+      setBox({ top: rect.bottom + 4, left: rect.left, width: rect.width });
+    };
+    measure();
+
+    // The field is flex-sized, so it moves with the sidebar and the window;
+    // either observer alone misses one of the two.
+    const observer = typeof ResizeObserver !== "undefined" ? new ResizeObserver(measure) : null;
+    observer?.observe(anchor);
+    if (anchor.parentElement) observer?.observe(anchor.parentElement);
+    window.addEventListener("resize", measure);
+    return () => {
+      observer?.disconnect();
+      window.removeEventListener("resize", measure);
+    };
+  }, [anchor]);
+
+  return box;
+}
diff --git a/components/settings/layout-settings.tsx b/components/settings/layout-settings.tsx
index 8d093cd52..d304076ac 100644
--- a/components/settings/layout-settings.tsx
+++ b/components/settings/layout-settings.tsx
@@ -3,7 +3,7 @@
 import { useMemo } from 'react';
 import { useTranslations } from 'next-intl';
 import { Check, Folder } from '@/components/icons';
-import { useSettingsStore, type ToolbarPosition, type MailLayout } from '@/stores/settings-store';
+import { useSettingsStore, type ToolbarPosition, type MailLayout, type InterfaceLayout } from '@/stores/settings-store';
 import { SettingsSection, SettingItem, RadioGroup, ToggleSwitch } from './settings-section';
 import { cn } from '@/lib/utils';
 import { usePolicyStore } from '@/stores/policy-store';
@@ -118,7 +118,7 @@ function MailLayoutPreview({
 export function LayoutSettings() {
   const t = useTranslations('settings.appearance');
   const tEmail = useTranslations('settings.email_behavior');
-  const { toolbarPosition, showToolbarLabels, hideAccountSwitcher, showRailAccountList, enableUnifiedMailbox, includeGroupInUnified, unifiedCrossAccount, allMailFolderIds, enableCrossUnreadView, enableCrossStarredView, enableCrossAllView, colorfulSidebarIcons, tintListRowsByTag, tintListRowsByAccount, showFolderTotalCount, faviconUnreadBadge, mailLayout, proInterface, updateSetting } = useSettingsStore();
+  const { toolbarPosition, showToolbarLabels, hideAccountSwitcher, showRailAccountList, enableUnifiedMailbox, includeGroupInUnified, unifiedCrossAccount, allMailFolderIds, enableCrossUnreadView, enableCrossStarredView, enableCrossAllView, colorfulSidebarIcons, tintListRowsByTag, tintListRowsByAccount, showFolderTotalCount, faviconUnreadBadge, mailLayout, proInterface, interfaceLayout, updateSetting } = useSettingsStore();
   const { isSettingLocked, isSettingHidden, isFeatureEnabled } = usePolicyStore();
   const accounts = useAccountStore(s => s.accounts);
   const activeAccountId = useAccountStore(s => s.activeAccountId);
@@ -168,6 +168,20 @@ export function LayoutSettings() {
 
   return (
     <SettingsSection title={t('title')} description={t('description')}>
+      {/* The interface layout decides where search, navigation and toolbars
+          go - a layout choice, so it leads the Layout tab. */}
+      {!isSettingHidden('interfaceLayout') && (
+      <SettingItem label={t('interface_layout.label')} description={t('interface_layout.description')} locked={isSettingLocked('interfaceLayout')}>
+        <RadioGroup
+          value={interfaceLayout}
+          onChange={(value) => updateSetting('interfaceLayout', value as InterfaceLayout)}
+          options={[
+            { value: 'default', label: t('interface_layout.default') },
+            { value: 'mountain-view', label: t('interface_layout.mountain_view') },
+          ]}
+        />
+      </SettingItem>
+      )}
       {!isSettingHidden('mailLayout') && (
       <SettingItem label={tEmail('mail_layout.label')} description={tEmail('mail_layout.description')} locked={isSettingLocked('mailLayout')}>
         <div className="w-[22rem] max-w-full">
diff --git a/components/settings/reading-settings.tsx b/components/settings/reading-settings.tsx
index 80e93a6f0..2e05af896 100644
--- a/components/settings/reading-settings.tsx
+++ b/components/settings/reading-settings.tsx
@@ -3,6 +3,7 @@
 import { useState } from 'react';
 import { useTranslations } from 'next-intl';
 import { useSettingsStore } from '@/stores/settings-store';
+import { useEffectiveMailLayout } from '@/hooks/use-effective-mail-layout';
 import type { ArchiveMode, HoverAction } from '@/stores/settings-store';
 import { ALL_HOVER_ACTIONS } from '@/stores/settings-store';
 import { useAuthStore } from '@/stores/auth-store';
@@ -28,7 +29,6 @@ export function ReadingSettings() {
     clearSearchOnFolderChange,
     showPreview,
     showVerificationCodes,
-    mailLayout,
     disableThreading,
     emailsPerPage,
     mailAttachmentAction,
@@ -44,7 +44,7 @@ export function ReadingSettings() {
     updateSetting,
   } = useSettingsStore();
 
-  const isFocusedLayout = mailLayout === 'focus';
+  const isFocusedLayout = useEffectiveMailLayout() === 'focus';
 
   const handleReorganizeArchive = async () => {
     const { client } = useAuthStore.getState();
diff --git a/hooks/use-effective-mail-layout.ts b/hooks/use-effective-mail-layout.ts
new file mode 100644
index 000000000..9a717ab70
--- /dev/null
+++ b/hooks/use-effective-mail-layout.ts
@@ -0,0 +1,8 @@
+"use client";
+
+import { effectiveMailLayout, useSettingsStore, type MailLayout } from "@/stores/settings-store";
+
+/** The mail layout in force: the saved one, or `focus` under Mountain View. */
+export function useEffectiveMailLayout(): MailLayout {
+  return useSettingsStore((state) => effectiveMailLayout(state.mailLayout, state.interfaceLayout));
+}
diff --git a/hooks/use-keyboard-shortcuts.ts b/hooks/use-keyboard-shortcuts.ts
index 7100d4868..21e9231cc 100644
--- a/hooks/use-keyboard-shortcuts.ts
+++ b/hooks/use-keyboard-shortcuts.ts
@@ -3,6 +3,7 @@
 import { useEffect, useCallback, useRef } from "react";
 import { Email } from "@/lib/jmap/types";
 import { isEditableEventTarget } from "@/lib/keyboard";
+import type { InterfaceLayout } from "@/stores/settings-store";
 
 export interface KeyboardShortcutHandlers {
   // Navigation
@@ -34,10 +35,34 @@ export interface KeyboardShortcutHandlers {
 
   // Thread actions
   onToggleThreadExpansion?: () => void;
+
+  /** Mountain View's `x`: put the focused conversation in or out of the selection. */
+  onToggleSelection?: () => void;
+  /** Mountain View's `g` sequences: `g` then i / s / t / d / a. */
+  onGoToMailbox?: (target: GoToMailboxTarget) => void;
 }
 
+export type GoToMailboxTarget = 'inbox' | 'starred' | 'sent' | 'drafts' | 'all';
+
+/** The letter each `g` sequence ends on. */
+const GO_TO_KEYS: Record<string, GoToMailboxTarget> = {
+  i: 'inbox',
+  s: 'starred',
+  t: 'sent',
+  d: 'drafts',
+  a: 'all',
+};
+
+/** How long a pending `g` waits for its second key before lapsing. */
+const GO_TO_SEQUENCE_MS = 1500;
+
 export interface UseKeyboardShortcutsOptions {
   enabled?: boolean;
+  /**
+   * Mountain View assigns `x` to selection rather than to thread expansion,
+   * and enables the `g` sequences.
+   */
+  mountainViewKeys?: boolean;
   emails: Email[];
   selectedEmailId?: string;
   selectionCount?: number;
@@ -69,12 +94,17 @@ function physicalShortcutKey(event: KeyboardEvent): string {
 
 export function useKeyboardShortcuts({
   enabled = true,
+  mountainViewKeys = false,
   emails,
   selectedEmailId,
   selectionCount = 0,
   handlers,
 }: UseKeyboardShortcutsOptions) {
   const handlersRef = useRef(handlers);
+  // A `g` waiting for the letter that completes it. Held in a ref so the
+  // listener stays stable; cleared on timeout, on completion, and on any key
+  // that isn't part of a sequence.
+  const pendingGoTo = useRef<ReturnType<typeof setTimeout> | null>(null);
 
   // Keep handlers ref updated
   useEffect(() => {
@@ -108,6 +138,19 @@ export function useKeyboardShortcuts({
 
       const hasBatchTarget = !!selectedEmailId || selectionCount > 0;
 
+      // Second half of a `g` sequence. Checked before the switch so `s`, `t`,
+      // `a` and `d` reach the folder jump instead of star / reply-all.
+      if (mountainViewKeys && pendingGoTo.current !== null) {
+        clearTimeout(pendingGoTo.current);
+        pendingGoTo.current = null;
+        const target = GO_TO_KEYS[key];
+        if (target && h.onGoToMailbox) {
+          event.preventDefault();
+          h.onGoToMailbox(target);
+          return;
+        }
+      }
+
       switch (key) {
         // Navigation
         case "j":
@@ -226,21 +269,44 @@ export function useKeyboardShortcuts({
           if (event.shiftKey) {
             event.preventDefault();
             h.onRefresh?.();
+          } else if (mountainViewKeys && h.onGoToMailbox) {
+            // Arm the sequence; the next key either completes it or lapses.
+            event.preventDefault();
+            pendingGoTo.current = setTimeout(() => {
+              pendingGoTo.current = null;
+            }, GO_TO_SEQUENCE_MS);
           }
           break;
 
         // Thread actions
         case "x":
-          if (selectedEmailId) {
+          if (mountainViewKeys) {
+            if (selectedEmailId) {
+              event.preventDefault();
+              h.onToggleSelection?.();
+            }
+          } else if (selectedEmailId) {
             event.preventDefault();
             h.onToggleThreadExpansion?.();
           }
           break;
       }
     },
-    [selectedEmailId, selectionCount]
+    [selectedEmailId, selectionCount, mountainViewKeys]
   );
 
+  // A pending sequence must not outlive the hook.
+  useEffect(() => () => {
+    if (pendingGoTo.current !== null) clearTimeout(pendingGoTo.current);
+  }, []);
+
+  useEffect(() => {
+    if (!mountainViewKeys && pendingGoTo.current !== null) {
+      clearTimeout(pendingGoTo.current);
+      pendingGoTo.current = null;
+    }
+  }, [mountainViewKeys]);
+
   useEffect(() => {
     if (!enabled) return;
 
@@ -273,6 +339,16 @@ export function useKeyboardShortcuts({
   return { getAdjacentEmailIndex };
 }
 
+/**
+ * One row of the help modal. `layout` limits a row to one interface layout:
+ * Mountain View adds the `g` sequences and gives `x` to selection.
+ */
+export interface ShortcutEntry {
+  readonly key: string;
+  readonly description: string;
+  readonly layout?: InterfaceLayout;
+}
+
 // Shortcut definitions for the help modal
 export const KEYBOARD_SHORTCUTS = {
   navigation: [
@@ -280,6 +356,7 @@ export const KEYBOARD_SHORTCUTS = {
     { key: "k / ↑", description: "shortcuts.navigation.previous_email" },
     { key: "Enter / o", description: "shortcuts.navigation.open_email" },
     { key: "Esc", description: "shortcuts.navigation.close_email" },
+    { key: "g → i / s / t / d / a", description: "shortcuts.navigation.go_to_folder", layout: "mountain-view" },
   ],
   actions: [
     { key: "r", description: "shortcuts.actions.reply" },
@@ -301,7 +378,8 @@ export const KEYBOARD_SHORTCUTS = {
     { key: "Ctrl + A", description: "shortcuts.global.select_all" },
   ],
   threads: [
-    { key: "x", description: "shortcuts.threads.expand_collapse" },
+    { key: "x", description: "shortcuts.threads.expand_collapse", layout: "default" },
+    { key: "x", description: "shortcuts.threads.select_mountain_view", layout: "mountain-view" },
   ],
   composer: [
     { key: "Ctrl/Cmd + Enter", description: "shortcuts.composer.send" },
diff --git a/hooks/use-pro-multi-account-mailboxes.ts b/hooks/use-pro-multi-account-mailboxes.ts
index 96f38c954..854c2dba3 100644
--- a/hooks/use-pro-multi-account-mailboxes.ts
+++ b/hooks/use-pro-multi-account-mailboxes.ts
@@ -14,6 +14,12 @@ import type { IJMAPClient } from "@/lib/jmap/client-interface";
  * sidebar reads this cache to render a Thunderbird-style per-account folder
  * tree (see [[project_pro_mode]]). Outside Pro the cache stays empty.
  *
+ * Mountain View needs the same cache for a different reason: its account
+ * popover puts the unread waiting in each account next to that address, and
+ * the active login's folder list knows nothing about the others. It is only
+ * worth the extra round trips once a second account is connected - with one
+ * account the popover has nothing to compare.
+ *
  * Each login is loaded once per client, not once per connection: while a
  * browser restores its logins they connect one after another, and reloading
  * every connected account on each connection cost 1 + 2 + … + N folder lists
@@ -25,6 +31,7 @@ import type { IJMAPClient } from "@/lib/jmap/client-interface";
 export function useProMultiAccountMailboxes(): void {
   const isEmbedded = useIsEmbedded();
   const proInterface = useSettingsStore((s) => s.proInterface);
+  const mountainView = useSettingsStore((s) => s.interfaceLayout === "mountain-view");
   // The ids of the connected logins, as one string: `accounts` itself changes
   // for display-name and login-time updates that call for no fetch at all.
   const connectedSignature = useAccountStore((s) =>
@@ -35,8 +42,8 @@ export function useProMultiAccountMailboxes(): void {
   const lastActive = useRef<string | null>(null);
 
   useEffect(() => {
-    if (!proInterface && !isEmbedded) return;
     const connected = connectedSignature ? connectedSignature.split("\n") : [];
+    if (!proInterface && !isEmbedded && !(mountainView && connected.length > 1)) return;
     if (connected.length === 0) return;
 
     if (lastActive.current !== null && lastActive.current !== activeAccountId) {
@@ -58,5 +65,5 @@ export function useProMultiAccountMailboxes(): void {
         if (!ok && loaded.current.get(id) === client) loaded.current.delete(id);
       });
     }
-  }, [proInterface, isEmbedded, connectedSignature, activeAccountId]);
+  }, [proInterface, isEmbedded, mountainView, connectedSignature, activeAccountId]);
 }
diff --git a/lib/__tests__/account-inbox-unread.test.ts b/lib/__tests__/account-inbox-unread.test.ts
new file mode 100644
index 000000000..950cf5e59
--- /dev/null
+++ b/lib/__tests__/account-inbox-unread.test.ts
@@ -0,0 +1,64 @@
+import { describe, it, expect } from 'vitest';
+import { inboxUnread, totalInboxUnread } from '../account-inbox-unread';
+import type { Mailbox } from '../jmap/types';
+
+const makeMailbox = (overrides: Partial<Mailbox> = {}): Mailbox => ({
+  id: 'mb-1',
+  name: 'Inbox',
+  role: 'inbox',
+  sortOrder: 0,
+  totalEmails: 10,
+  unreadEmails: 3,
+  totalThreads: 10,
+  unreadThreads: 3,
+  isSubscribed: true,
+  myRights: {
+    mayReadItems: true,
+    mayAddItems: true,
+    mayRemoveItems: true,
+    maySetSeen: true,
+    maySetKeywords: true,
+    mayCreateChild: true,
+    mayRename: true,
+    mayDelete: true,
+    maySubmit: true,
+  },
+  ...overrides,
+});
+
+describe('inboxUnread', () => {
+  it('reads the unread count off the account\'s own inbox', () => {
+    expect(inboxUnread([makeMailbox({ unreadEmails: 7 })])).toBe(7);
+  });
+
+  it('tells "not loaded yet" apart from a real zero', () => {
+    expect(inboxUnread(undefined)).toBeUndefined();
+    expect(inboxUnread([])).toBeUndefined();
+    expect(inboxUnread([makeMailbox({ unreadEmails: 0 })])).toBe(0);
+  });
+
+  it('ignores a shared inbox, which belongs to somebody else', () => {
+    const shared = makeMailbox({ id: 'mb-shared', isShared: true, unreadEmails: 99 });
+    expect(inboxUnread([shared])).toBeUndefined();
+    expect(inboxUnread([shared, makeMailbox({ unreadEmails: 2 })])).toBe(2);
+  });
+
+  it('has nothing to report for an account with no inbox role', () => {
+    expect(inboxUnread([makeMailbox({ role: 'archive' })])).toBeUndefined();
+  });
+});
+
+describe('totalInboxUnread', () => {
+  it('adds up the accounts it was asked about, and only those', () => {
+    const byAccount = {
+      a: [makeMailbox({ unreadEmails: 4 })],
+      b: [makeMailbox({ unreadEmails: 5 })],
+      c: [makeMailbox({ unreadEmails: 100 })],
+    };
+    expect(totalInboxUnread(['a', 'b'], byAccount)).toBe(9);
+  });
+
+  it('counts an account whose folders have not arrived as nothing', () => {
+    expect(totalInboxUnread(['a', 'b'], { a: [makeMailbox({ unreadEmails: 4 })] })).toBe(4);
+  });
+});
diff --git a/lib/account-inbox-unread.ts b/lib/account-inbox-unread.ts
new file mode 100644
index 000000000..1ea8ea67f
--- /dev/null
+++ b/lib/account-inbox-unread.ts
@@ -0,0 +1,35 @@
+import type { Mailbox } from "@/lib/jmap/types";
+
+/**
+ * Unread messages waiting in an account's own inbox.
+ *
+ * Mountain View's account popover puts this number next to every address, so
+ * that switching account is a decision one can take from the popover instead
+ * of having to visit each account in turn.
+ *
+ * Shared folders are skipped: they are someone else's inbox, they are listed
+ * under their owner in the sidebar, and counting them here would attribute
+ * another person's unread mail to this account. `undefined` means "not known
+ * yet" - the account's folders have not been fetched - and is deliberately
+ * distinct from a known zero, which the caller should render as no badge
+ * rather than as a "0".
+ */
+export function inboxUnread(mailboxes: Mailbox[] | undefined): number | undefined {
+  if (!mailboxes || mailboxes.length === 0) return undefined;
+  const inbox = mailboxes.find((mailbox) => mailbox.role === "inbox" && !mailbox.isShared);
+  return inbox ? inbox.unreadEmails : undefined;
+}
+
+/**
+ * What "All inboxes" carries: the unread of every listed account's inbox.
+ *
+ * Accounts whose folders are still loading contribute nothing rather than
+ * blocking the total, so the badge grows as the fetches land instead of
+ * appearing all at once several seconds in.
+ */
+export function totalInboxUnread(
+  accountIds: readonly string[],
+  mailboxesByAccount: Record<string, Mailbox[] | undefined>
+): number {
+  return accountIds.reduce((total, id) => total + (inboxUnread(mailboxesByAccount[id]) ?? 0), 0);
+}
diff --git a/locales/ar/common.json b/locales/ar/common.json
index 9248fb471..12dcadee8 100644
--- a/locales/ar/common.json
+++ b/locales/ar/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "إظهار الكل ({count})",
     "show_fewer_tags": "إظهار أقل",
     "folders": "المجلدات",
+    "show_more": "المزيد",
+    "show_fewer": "أقل",
     "shared": "مشترك",
     "mail": "البريد",
     "nav_label": "التنقل",
@@ -237,6 +239,7 @@
     "replied": "تم الرد عليها",
     "forwarded": "تمت إعادة توجيهها",
     "has_attachment": "تحتوي على مرفق",
+    "conversations_range": "{from}–{to, number} من {total, number}",
     "conversations_count": "{count} من {total} محادثة",
     "conversations_count_plus": "{count}+ محادثة",
     "conversations_count_simple": "{count} محادثة",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "تصغير",
+    "maximize": "ملء الشاشة",
+    "restore": "استعادة",
     "read_receipt_on": "إيصال القراءة مطلوب (انقر للتعطيل)",
     "read_receipt_off": "طلب إيصال قراءة",
     "dsn_on": "تم طلب إشعار التسليم (انقر للتعطيل)",
@@ -1071,6 +1077,12 @@
         "regular": "عادي",
         "comfortable": "مريح"
       },
+      "interface_layout": {
+        "label": "تخطيط الواجهة",
+        "description": "موضع البحث والتنقل وأشرطة الأدوات",
+        "default": "افتراضي",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "تفعيل الحركات",
         "description": "إظهار الانتقالات والتأثيرات السلسة"
@@ -2444,7 +2456,8 @@
       "next_email": "الرسالة التالية",
       "previous_email": "الرسالة السابقة",
       "open_email": "فتح الرسالة",
-      "close_email": "إغلاق / إلغاء التحديد"
+      "close_email": "إغلاق / إلغاء التحديد",
+      "go_to_folder": "الانتقال إلى المجلد"
     },
     "actions": {
       "reply": "رد",
@@ -2466,7 +2479,8 @@
       "global_search": "البحث في كل شيء"
     },
     "threads": {
-      "expand_collapse": "توسيع/طي المحادثة"
+      "expand_collapse": "توسيع/طي المحادثة",
+      "select_mountain_view": "تحديد المحادثة"
     },
     "composer": {
       "send": "إرسال الرسالة",
diff --git a/locales/ca/common.json b/locales/ca/common.json
index 7c0058a89..3535e5b6c 100644
--- a/locales/ca/common.json
+++ b/locales/ca/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Mostra-ho tot ({count})",
     "show_fewer_tags": "Mostra'n menys",
     "folders": "Carpetes",
+    "show_more": "Més",
+    "show_fewer": "Menys",
     "shared": "Compartit",
     "mail": "Correu",
     "nav_label": "Navegació",
@@ -237,6 +239,7 @@
     "replied": "Respost",
     "forwarded": "Reenviat",
     "has_attachment": "Té adjunt",
+    "conversations_range": "{from}–{to, number} de {total, number}",
     "conversations_count": "{count} de {total} converses",
     "conversations_count_plus": "{count}+ converses",
     "conversations_count_simple": "{count} converses",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimitza",
+    "maximize": "Pantalla completa",
+    "restore": "Restaura",
     "read_receipt_on": "Confirmació de lectura sol·licitada (feu clic per desactivar-la)",
     "read_receipt_off": "Sol·licita una confirmació de lectura",
     "dsn_on": "Notificació de lliurament sol·licitada (fes clic per desactivar)",
@@ -1071,6 +1077,12 @@
         "regular": "Normal",
         "comfortable": "Còmoda"
       },
+      "interface_layout": {
+        "label": "Disposició de la interfície",
+        "description": "On se situen la cerca, la navegació i les barres d'eines",
+        "default": "Predeterminat",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Activa les animacions",
         "description": "Mostra transicions i efectes suaus"
@@ -2444,7 +2456,8 @@
       "next_email": "Correu següent",
       "previous_email": "Correu anterior",
       "open_email": "Obre el correu",
-      "close_email": "Tanca / Desselecciona"
+      "close_email": "Tanca / Desselecciona",
+      "go_to_folder": "Vés a la carpeta"
     },
     "actions": {
       "reply": "Respon",
@@ -2466,7 +2479,8 @@
       "global_search": "Cerca-ho tot"
     },
     "threads": {
-      "expand_collapse": "Desplega/replega el fil"
+      "expand_collapse": "Desplega/replega el fil",
+      "select_mountain_view": "Selecciona la conversa"
     },
     "composer": {
       "send": "Envia el correu",
diff --git a/locales/cs/common.json b/locales/cs/common.json
index 487eb7fa7..aa92f59b5 100644
--- a/locales/cs/common.json
+++ b/locales/cs/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Zobrazit vše ({count})",
     "show_fewer_tags": "Zobrazit méně",
     "folders": "Složky",
+    "show_more": "Více",
+    "show_fewer": "Méně",
     "shared": "Sdílené",
     "mail": "Pošta",
     "nav_label": "Navigace",
@@ -237,6 +239,7 @@
     "replied": "Zodpovězeno",
     "forwarded": "Přeposláno",
     "has_attachment": "Obsahuje přílohu",
+    "conversations_range": "{from}–{to, number} z {total, number}",
     "conversations_count": "{count} z {total} konverzací",
     "conversations_count_plus": "Více než {count} konverzací",
     "conversations_count_simple": "{count} konverzací",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimalizovat",
+    "maximize": "Celá obrazovka",
+    "restore": "Obnovit",
     "read_receipt_on": "Vyžádáno potvrzení o přečtení (kliknutím vypnete)",
     "read_receipt_off": "Vyžádat potvrzení o přečtení",
     "dsn_on": "Oznámení o doručení vyžádáno (kliknutím vypnete)",
@@ -1068,6 +1074,12 @@
         "regular": "Běžná",
         "comfortable": "Pohodlná"
       },
+      "interface_layout": {
+        "label": "Rozvržení rozhraní",
+        "description": "Kde se nachází hledání, navigace a panely nástrojů",
+        "default": "Výchozí",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Povolit animace",
         "description": "Zobrazovat plynulé přechody a efekty"
@@ -2444,7 +2456,8 @@
       "next_email": "Další zpráva",
       "previous_email": "Předchozí zpráva",
       "open_email": "Otevřít zprávu",
-      "close_email": "Zavřít / Zrušit výběr"
+      "close_email": "Zavřít / Zrušit výběr",
+      "go_to_folder": "Přejít do složky"
     },
     "actions": {
       "reply": "Odpovědět",
@@ -2466,7 +2479,8 @@
       "global_search": "Hledat ve všem"
     },
     "threads": {
-      "expand_collapse": "Rozbalit/sbalit vlákno"
+      "expand_collapse": "Rozbalit/sbalit vlákno",
+      "select_mountain_view": "Vybrat konverzaci"
     },
     "composer": {
       "send": "Odeslat e-mail",
diff --git a/locales/da/common.json b/locales/da/common.json
index 4787b5624..75f3843a9 100644
--- a/locales/da/common.json
+++ b/locales/da/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Vis alle ({count})",
     "show_fewer_tags": "Vis færre",
     "folders": "Mapper",
+    "show_more": "Mere",
+    "show_fewer": "Mindre",
     "shared": "Delt",
     "mail": "Mail",
     "nav_label": "Navigation",
@@ -237,6 +239,7 @@
     "replied": "Besvaret",
     "forwarded": "Videresendt",
     "has_attachment": "Har vedhæftning",
+    "conversations_range": "{from}–{to, number} af {total, number}",
     "conversations_count": "{count} af {total} samtaler",
     "conversations_count_plus": "{count}+ samtaler",
     "conversations_count_simple": "{count} samtaler",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimer",
+    "maximize": "Fuld skærm",
+    "restore": "Gendan",
     "read_receipt_on": "Læsekvittering anmodet (klik for at deaktivere)",
     "read_receipt_off": "Anmod om læsekvittering",
     "dsn_on": "Leveringsbesked anmodet (klik for at slå fra)",
@@ -1071,6 +1077,12 @@
         "regular": "Almindelig",
         "comfortable": "Komfortabel"
       },
+      "interface_layout": {
+        "label": "Grænsefladelayout",
+        "description": "Hvor søgning, navigation og værktøjslinjer er placeret",
+        "default": "Standard",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Aktivér animationer",
         "description": "Vis glatte overgange og effekter"
@@ -2444,7 +2456,8 @@
       "next_email": "Næste e-mail",
       "previous_email": "Forrige e-mail",
       "open_email": "Åbn e-mail",
-      "close_email": "Luk / Fravaælg"
+      "close_email": "Luk / Fravaælg",
+      "go_to_folder": "Gå til mappe"
     },
     "actions": {
       "reply": "Svar",
@@ -2466,7 +2479,8 @@
       "global_search": "Søg i alt"
     },
     "threads": {
-      "expand_collapse": "Udvid/skjul tråd"
+      "expand_collapse": "Udvid/skjul tråd",
+      "select_mountain_view": "Vælg samtalen"
     },
     "composer": {
       "send": "Send e-mail",
diff --git a/locales/de/common.json b/locales/de/common.json
index 46a6edd21..f1b6a6fba 100644
--- a/locales/de/common.json
+++ b/locales/de/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Alle anzeigen ({count})",
     "show_fewer_tags": "Weniger anzeigen",
     "folders": "Ordner",
+    "show_more": "Mehr",
+    "show_fewer": "Weniger",
     "mail": "E-Mail",
     "nav_label": "Navigation",
     "add_app": "Apps",
@@ -237,6 +239,7 @@
     "replied": "Beantwortet",
     "forwarded": "Weitergeleitet",
     "has_attachment": "Mit Anhang",
+    "conversations_range": "{from}–{to, number} von {total, number}",
     "conversations_count": "{count} von {total} Unterhaltungen",
     "conversations_count_plus": "{count}+ Unterhaltungen",
     "conversations_count_simple": "{count} Unterhaltungen",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimieren",
+    "maximize": "Vollbild",
+    "restore": "Wiederherstellen",
     "read_receipt_on": "Lesebestätigung angefordert (klicken zum Deaktivieren)",
     "read_receipt_off": "Lesebestätigung anfordern",
     "dsn_on": "Zustellbenachrichtigung angefordert (zum Deaktivieren klicken)",
@@ -1068,6 +1074,12 @@
         "regular": "Normal",
         "comfortable": "Komfortabel"
       },
+      "interface_layout": {
+        "label": "Oberflächen-Layout",
+        "description": "Wo Suche, Navigation und Symbolleisten liegen",
+        "default": "Standard",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Animationen aktivieren",
         "description": "Weiche Übergänge und Effekte anzeigen"
@@ -2444,7 +2456,8 @@
       "next_email": "Nächste E-Mail",
       "previous_email": "Vorherige E-Mail",
       "open_email": "E-Mail öffnen",
-      "close_email": "Schließen / Auswahl aufheben"
+      "close_email": "Schließen / Auswahl aufheben",
+      "go_to_folder": "Zum Ordner springen"
     },
     "actions": {
       "reply": "Antworten",
@@ -2466,7 +2479,8 @@
       "global_search": "Alles durchsuchen"
     },
     "threads": {
-      "expand_collapse": "Unterhaltung erweitern/einklappen"
+      "expand_collapse": "Unterhaltung erweitern/einklappen",
+      "select_mountain_view": "Konversation auswählen"
     },
     "composer": {
       "send": "E-Mail senden",
diff --git a/locales/en/common.json b/locales/en/common.json
index d1d2115fa..40e847994 100644
--- a/locales/en/common.json
+++ b/locales/en/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Show all ({count})",
     "show_fewer_tags": "Show less",
     "folders": "Folders",
+    "show_more": "More",
+    "show_fewer": "Less",
     "shared": "Shared",
     "mail": "Mail",
     "nav_label": "Navigation",
@@ -237,6 +239,7 @@
     "replied": "Replied",
     "forwarded": "Forwarded",
     "has_attachment": "Has attachment",
+    "conversations_range": "{from}–{to, number} of {total, number}",
     "conversations_count": "{count} of {total} conversations",
     "conversations_count_plus": "{count}+ conversations",
     "conversations_count_simple": "{count} conversations",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimize",
+    "maximize": "Full screen",
+    "restore": "Restore",
     "read_receipt_on": "Read receipt requested (click to disable)",
     "read_receipt_off": "Request a read receipt",
     "dsn_on": "Delivery notification requested (click to disable)",
@@ -1071,6 +1077,12 @@
         "regular": "Regular",
         "comfortable": "Comfortable"
       },
+      "interface_layout": {
+        "label": "Interface layout",
+        "description": "Where search, navigation and toolbars sit",
+        "default": "Default",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Enable Animations",
         "description": "Show smooth transitions and effects"
@@ -2444,7 +2456,8 @@
       "next_email": "Next email",
       "previous_email": "Previous email",
       "open_email": "Open email",
-      "close_email": "Close / Deselect"
+      "close_email": "Close / Deselect",
+      "go_to_folder": "Go to folder"
     },
     "actions": {
       "reply": "Reply",
@@ -2466,7 +2479,8 @@
       "global_search": "Search everything"
     },
     "threads": {
-      "expand_collapse": "Expand/collapse thread"
+      "expand_collapse": "Expand/collapse thread",
+      "select_mountain_view": "Select the conversation"
     },
     "composer": {
       "send": "Send email",
diff --git a/locales/es/common.json b/locales/es/common.json
index 111980e64..cc11ad7b6 100644
--- a/locales/es/common.json
+++ b/locales/es/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Mostrar todo ({count})",
     "show_fewer_tags": "Mostrar menos",
     "folders": "Carpetas",
+    "show_more": "Más",
+    "show_fewer": "Menos",
     "mail": "Correo",
     "nav_label": "Navegación",
     "add_app": "Apps",
@@ -237,6 +239,7 @@
     "replied": "Respondido",
     "forwarded": "Reenviado",
     "has_attachment": "Tiene adjunto",
+    "conversations_range": "{from}–{to, number} de {total, number}",
     "conversations_count": "{count} de {total} conversaciones",
     "conversations_count_plus": "{count}+ conversaciones",
     "conversations_count_simple": "{count} conversaciones",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimizar",
+    "maximize": "Pantalla completa",
+    "restore": "Restaurar",
     "read_receipt_on": "Confirmación de lectura solicitada (haz clic para desactivar)",
     "read_receipt_off": "Solicitar confirmación de lectura",
     "dsn_on": "Notificación de entrega solicitada (clic para desactivar)",
@@ -1068,6 +1074,12 @@
         "regular": "Normal",
         "comfortable": "Cómodo"
       },
+      "interface_layout": {
+        "label": "Diseño de la interfaz",
+        "description": "Dónde se sitúan la búsqueda, la navegación y las barras de herramientas",
+        "default": "Predeterminado",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Habilitar Animaciones",
         "description": "Mostrar transiciones y efectos suaves"
@@ -2444,7 +2456,8 @@
       "next_email": "Siguiente correo",
       "previous_email": "Correo anterior",
       "open_email": "Abrir correo",
-      "close_email": "Cerrar / Deseleccionar"
+      "close_email": "Cerrar / Deseleccionar",
+      "go_to_folder": "Ir a la carpeta"
     },
     "actions": {
       "reply": "Responder",
@@ -2466,7 +2479,8 @@
       "global_search": "Buscar en todo"
     },
     "threads": {
-      "expand_collapse": "Expandir/contraer conversación"
+      "expand_collapse": "Expandir/contraer conversación",
+      "select_mountain_view": "Seleccionar la conversación"
     },
     "composer": {
       "send": "Enviar correo",
diff --git a/locales/fa/common.json b/locales/fa/common.json
index 8492e987e..d60cd82cd 100644
--- a/locales/fa/common.json
+++ b/locales/fa/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "نمایش همه ({count})",
     "show_fewer_tags": "نمایش کمتر",
     "folders": "پوشه‌ها",
+    "show_more": "بیشتر",
+    "show_fewer": "کمتر",
     "shared": "اشتراکی",
     "mail": "ایمیل",
     "nav_label": "ناوبری",
@@ -237,6 +239,7 @@
     "replied": "پاسخ داده شده",
     "forwarded": "بازارسال شده",
     "has_attachment": "دارای پیوست",
+    "conversations_range": "{from}–{to, number} از {total, number}",
     "conversations_count": "{count} از {total} مکالمه",
     "conversations_count_plus": "+{count} مکالمه",
     "conversations_count_simple": "{count} مکالمه",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "کوچک کردن",
+    "maximize": "تمام‌صفحه",
+    "restore": "بازگردانی",
     "read_receipt_on": "درخواست تأیید خواندن فعال (کلیک برای غیرفعال کردن)",
     "read_receipt_off": "درخواست تأیید خواندن",
     "dsn_on": "اعلان تحویل درخواست شد (برای غیرفعال کردن کلیک کنید)",
@@ -1071,6 +1077,12 @@
         "regular": "معمولی",
         "comfortable": "راحت"
       },
+      "interface_layout": {
+        "label": "چیدمان رابط",
+        "description": "جای جست‌وجو، ناوبری و نوارهای ابزار",
+        "default": "پیش‌فرض",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "فعال کردن انیمیشن‌ها",
         "description": "نمایش transitions و افکت‌های نرم"
@@ -2444,7 +2456,8 @@
       "next_email": "ایمیل بعدی",
       "previous_email": "ایمیل قبلی",
       "open_email": "باز کردن ایمیل",
-      "close_email": "بستن / لغو انتخاب"
+      "close_email": "بستن / لغو انتخاب",
+      "go_to_folder": "رفتن به پوشه"
     },
     "actions": {
       "reply": "پاسخ",
@@ -2466,7 +2479,8 @@
       "global_search": "جستجو در همه جا"
     },
     "threads": {
-      "expand_collapse": "باز/بسته کردن رشته"
+      "expand_collapse": "باز/بسته کردن رشته",
+      "select_mountain_view": "انتخاب گفت‌وگو"
     },
     "composer": {
       "send": "ارسال ایمیل",
diff --git a/locales/fr/common.json b/locales/fr/common.json
index 6c3d64b57..c88f85ad9 100644
--- a/locales/fr/common.json
+++ b/locales/fr/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Tout afficher ({count})",
     "show_fewer_tags": "Afficher moins",
     "folders": "Dossiers",
+    "show_more": "Plus",
+    "show_fewer": "Moins",
     "mail": "Messagerie",
     "nav_label": "Navigation",
     "add_app": "Apps",
@@ -237,6 +239,7 @@
     "replied": "Répondu",
     "forwarded": "Transféré",
     "has_attachment": "Avec pièce jointe",
+    "conversations_range": "{from}–{to, number} sur {total, number}",
     "conversations_count": "{count} sur {total} conversations",
     "conversations_count_plus": "{count}+ conversations",
     "conversations_count_simple": "{count} conversations",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Réduire",
+    "maximize": "Plein écran",
+    "restore": "Restaurer",
     "read_receipt_on": "Accusé de lecture demandé (cliquez pour désactiver)",
     "read_receipt_off": "Demander un accusé de lecture",
     "dsn_on": "Notification de remise demandée (cliquer pour désactiver)",
@@ -1068,6 +1074,12 @@
         "regular": "Normale",
         "comfortable": "Confortable"
       },
+      "interface_layout": {
+        "label": "Disposition de l'interface",
+        "description": "Où se trouvent la recherche, la navigation et les barres d'outils",
+        "default": "Par défaut",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Activer les animations",
         "description": "Afficher les transitions et effets fluides"
@@ -2444,7 +2456,8 @@
       "next_email": "Email suivant",
       "previous_email": "Email précédent",
       "open_email": "Ouvrir l'email",
-      "close_email": "Fermer / Désélectionner"
+      "close_email": "Fermer / Désélectionner",
+      "go_to_folder": "Aller au dossier"
     },
     "actions": {
       "reply": "Répondre",
@@ -2466,7 +2479,8 @@
       "global_search": "Tout rechercher"
     },
     "threads": {
-      "expand_collapse": "Développer/réduire la conversation"
+      "expand_collapse": "Développer/réduire la conversation",
+      "select_mountain_view": "Sélectionner la conversation"
     },
     "composer": {
       "send": "Envoyer l'e-mail",
diff --git a/locales/he/common.json b/locales/he/common.json
index 52252c30c..2b1282dd7 100644
--- a/locales/he/common.json
+++ b/locales/he/common.json
@@ -133,6 +133,8 @@
     "show_all_tags": "הצג הכל ({count})",
     "show_fewer_tags": "הצג פחות",
     "folders": "תיקיות",
+    "show_more": "עוד",
+    "show_fewer": "פחות",
     "mail": "דוֹאַר",
     "nav_label": "ניווט",
     "add_app": "אפליקציות",
@@ -202,6 +204,7 @@
     "replied": "נענה",
     "forwarded": "הועבר",
     "has_attachment": "כולל קובץ מצורף",
+    "conversations_range": "{from}–{to, number} מתוך {total, number}",
     "conversations_count": "{count}מתוך שיחות{total}",
     "conversations_count_plus": "{count}+ שיחות",
     "conversations_count_simple": "שיחות{count}",
@@ -562,6 +565,9 @@
     }
   },
   "email_composer": {
+    "minimize": "מזעור",
+    "maximize": "מסך מלא",
+    "restore": "שחזור",
     "new_message": "הודעה חדשה",
     "signature_edit_hint": "לחץ לחיצה כפולה לעריכת החתימה",
     "reply": "השב",
@@ -1033,6 +1039,12 @@
         "regular": "רגיל",
         "comfortable": "נוח"
       },
+      "interface_layout": {
+        "label": "פריסת הממשק",
+        "description": "היכן ממוקמים החיפוש, הניווט וסרגלי הכלים",
+        "default": "ברירת מחדל",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "הפעל אנימציות",
         "description": "הצג מעברים ואפקטים חלקים"
@@ -2368,7 +2380,8 @@
       "next_email": "המייל הבא",
       "previous_email": "אימייל קודם",
       "open_email": "פתח אימייל",
-      "close_email": "סגור / בטל בחירה"
+      "close_email": "סגור / בטל בחירה",
+      "go_to_folder": "מעבר לתיקייה"
     },
     "actions": {
       "reply": "השב",
@@ -2390,7 +2403,8 @@
       "global_search": "חיפוש בכל מקום"
     },
     "threads": {
-      "expand_collapse": "הרחב/כווץ את השרשור"
+      "expand_collapse": "הרחב/כווץ את השרשור",
+      "select_mountain_view": "בחירת השיחה"
     },
     "composer": {
       "template_picker": "פתח את בוחר התבניות",
diff --git a/locales/hu/common.json b/locales/hu/common.json
index d0f3b6949..a571f7b08 100644
--- a/locales/hu/common.json
+++ b/locales/hu/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Összes megjelenítése ({count})",
     "show_fewer_tags": "Kevesebb megjelenítése",
     "folders": "Mappák",
+    "show_more": "Több",
+    "show_fewer": "Kevesebb",
     "shared": "Megosztott",
     "mail": "Levelek",
     "nav_label": "Navigáció",
@@ -237,6 +239,7 @@
     "replied": "Megválaszolva",
     "forwarded": "Továbbítva",
     "has_attachment": "Melléklettel",
+    "conversations_range": "{from}–{to, number} / {total, number}",
     "conversations_count": "{count} / {total} beszélgetés",
     "conversations_count_plus": "{count}+ beszélgetés",
     "conversations_count_simple": "{count} beszélgetés",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Kis méret",
+    "maximize": "Teljes képernyő",
+    "restore": "Visszaállítás",
     "read_receipt_on": "Olvasási visszaigazolás kérve (kattints a letiltáshoz)",
     "read_receipt_off": "Olvasási visszaigazolás kérése",
     "dsn_on": "Kézbesítési értesítés kérve (kattints a kikapcsoláshoz)",
@@ -1071,6 +1077,12 @@
         "regular": "Normál",
         "comfortable": "Kényelmes"
       },
+      "interface_layout": {
+        "label": "Felület elrendezése",
+        "description": "Hol helyezkedik el a keresés, a navigáció és az eszköztárak",
+        "default": "Alapértelmezett",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Animációk engedélyezése",
         "description": "Simább átmenetek és effektek megjelenítése"
@@ -2444,7 +2456,8 @@
       "next_email": "Következő e-mail",
       "previous_email": "Előző e-mail",
       "open_email": "E-mail megnyitása",
-      "close_email": "Bezárás / Kijelölés megszüntetése"
+      "close_email": "Bezárás / Kijelölés megszüntetése",
+      "go_to_folder": "Ugrás mappára"
     },
     "actions": {
       "reply": "Válasz",
@@ -2466,7 +2479,8 @@
       "global_search": "Keresés mindenben"
     },
     "threads": {
-      "expand_collapse": "Beszélgetés kibontása/összecsukása"
+      "expand_collapse": "Beszélgetés kibontása/összecsukása",
+      "select_mountain_view": "Beszélgetés kijelölése"
     },
     "composer": {
       "send": "E-mail küldése",
diff --git a/locales/it/common.json b/locales/it/common.json
index 639257deb..f5f654815 100644
--- a/locales/it/common.json
+++ b/locales/it/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Mostra tutto ({count})",
     "show_fewer_tags": "Mostra meno",
     "folders": "Cartelle",
+    "show_more": "Altro",
+    "show_fewer": "Riduci",
     "mail": "Posta",
     "nav_label": "Navigazione",
     "add_app": "App",
@@ -237,6 +239,7 @@
     "replied": "Risposto",
     "forwarded": "Inoltrato",
     "has_attachment": "Con allegato",
+    "conversations_range": "{from}–{to, number} di {total, number}",
     "conversations_count": "{count} di {total} conversazioni",
     "conversations_count_plus": "{count}+ conversazioni",
     "conversations_count_simple": "{count} conversazioni",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Riduci a icona",
+    "maximize": "Schermo intero",
+    "restore": "Ripristina",
     "read_receipt_on": "Conferma di lettura richiesta (clicca per disattivare)",
     "read_receipt_off": "Richiedi una conferma di lettura",
     "dsn_on": "Notifica di consegna richiesta (clic per disattivare)",
@@ -1068,6 +1074,12 @@
         "regular": "Normale",
         "comfortable": "Comodo"
       },
+      "interface_layout": {
+        "label": "Layout dell'interfaccia",
+        "description": "Dove si trovano ricerca, navigazione e barre degli strumenti",
+        "default": "Predefinito",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Abilita animazioni",
         "description": "Mostra transizioni ed effetti fluidi"
@@ -2444,7 +2456,8 @@
       "next_email": "Messaggio successivo",
       "previous_email": "Messaggio precedente",
       "open_email": "Apri messaggio",
-      "close_email": "Chiudi / Deseleziona"
+      "close_email": "Chiudi / Deseleziona",
+      "go_to_folder": "Vai alla cartella"
     },
     "actions": {
       "reply": "Rispondi",
@@ -2466,7 +2479,8 @@
       "global_search": "Cerca ovunque"
     },
     "threads": {
-      "expand_collapse": "Espandi/comprimi conversazione"
+      "expand_collapse": "Espandi/comprimi conversazione",
+      "select_mountain_view": "Seleziona la conversazione"
     },
     "composer": {
       "send": "Invia email",
diff --git a/locales/ja/common.json b/locales/ja/common.json
index 434eead72..1fa546fba 100644
--- a/locales/ja/common.json
+++ b/locales/ja/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "すべて表示（{count}）",
     "show_fewer_tags": "表示を減らす",
     "folders": "フォルダ",
+    "show_more": "もっと見る",
+    "show_fewer": "折りたたむ",
     "mail": "メール",
     "nav_label": "ナビゲーション",
     "add_app": "アプリ",
@@ -237,6 +239,7 @@
     "replied": "返信済み",
     "forwarded": "転送済み",
     "has_attachment": "添付ファイルあり",
+    "conversations_range": "{total, number} 件中 {from}–{to, number} 件",
     "conversations_count": "{total}件中{count}件の会話",
     "conversations_count_plus": "{count}件以上の会話",
     "conversations_count_simple": "{count}件の会話",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "最小化",
+    "maximize": "全画面表示",
+    "restore": "元に戻す",
     "read_receipt_on": "開封確認を要求中（クリックで無効化）",
     "read_receipt_off": "開封確認を要求する",
     "dsn_on": "配信通知を要求中（クリックで解除）",
@@ -1068,6 +1074,12 @@
         "regular": "標準",
         "comfortable": "ゆったり"
       },
+      "interface_layout": {
+        "label": "インターフェースのレイアウト",
+        "description": "検索・ナビゲーション・ツールバーの配置",
+        "default": "デフォルト",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "アニメーションを有効にする",
         "description": "スムーズな遷移とエフェクトを表示"
@@ -2444,7 +2456,8 @@
       "next_email": "次のメール",
       "previous_email": "前のメール",
       "open_email": "メールを開く",
-      "close_email": "閉じる / 選択解除"
+      "close_email": "閉じる / 選択解除",
+      "go_to_folder": "フォルダーに移動"
     },
     "actions": {
       "reply": "返信",
@@ -2466,7 +2479,8 @@
       "global_search": "すべてを検索"
     },
     "threads": {
-      "expand_collapse": "スレッドの展開/折りたたみ"
+      "expand_collapse": "スレッドの展開/折りたたみ",
+      "select_mountain_view": "スレッドを選択"
     },
     "composer": {
       "send": "メールを送信",
diff --git a/locales/ko/common.json b/locales/ko/common.json
index 748bd553a..1a6855405 100644
--- a/locales/ko/common.json
+++ b/locales/ko/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "전체 보기({count})",
     "show_fewer_tags": "간략히 보기",
     "folders": "폴더",
+    "show_more": "더보기",
+    "show_fewer": "간략히",
     "mail": "메일",
     "nav_label": "내비게이션",
     "add_app": "앱",
@@ -237,6 +239,7 @@
     "replied": "답장함",
     "forwarded": "전달함",
     "has_attachment": "첨부 파일 있음",
+    "conversations_range": "{total, number}개 중 {from}–{to, number}",
     "conversations_count": "전체 {total}개 중 {count}개의 대화",
     "conversations_count_plus": "{count}개 이상의 대화",
     "conversations_count_simple": "{count}개의 대화",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "최소화",
+    "maximize": "전체 화면",
+    "restore": "복원",
     "read_receipt_on": "읽음 확인 요청됨 (클릭하여 해제)",
     "read_receipt_off": "읽음 확인 요청",
     "dsn_on": "배달 알림 요청됨 (클릭하여 해제)",
@@ -1068,6 +1074,12 @@
         "regular": "보통",
         "comfortable": "넓게"
       },
+      "interface_layout": {
+        "label": "인터페이스 레이아웃",
+        "description": "검색, 탐색, 도구 모음의 위치",
+        "default": "기본",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "애니메이션 켜기",
         "description": "부드러운 전환 효과를 사용해요"
@@ -2444,7 +2456,8 @@
       "next_email": "다음 메일",
       "previous_email": "이전 메일",
       "open_email": "메일 열기",
-      "close_email": "닫기 / 선택 해제"
+      "close_email": "닫기 / 선택 해제",
+      "go_to_folder": "폴더로 이동"
     },
     "actions": {
       "reply": "답장",
@@ -2466,7 +2479,8 @@
       "global_search": "전체 검색"
     },
     "threads": {
-      "expand_collapse": "대화 펼치기/접기"
+      "expand_collapse": "대화 펼치기/접기",
+      "select_mountain_view": "대화 선택"
     },
     "composer": {
       "send": "이메일 보내기",
diff --git a/locales/lv/common.json b/locales/lv/common.json
index e0d64b230..14745593c 100644
--- a/locales/lv/common.json
+++ b/locales/lv/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Rādīt visus ({count})",
     "show_fewer_tags": "Rādīt mazāk",
     "folders": "Mapes",
+    "show_more": "Vairāk",
+    "show_fewer": "Mazāk",
     "mail": "Pasts",
     "nav_label": "Navigācija",
     "add_app": "Lietotnes",
@@ -237,6 +239,7 @@
     "replied": "Atbildēts",
     "forwarded": "Pārsūtīts",
     "has_attachment": "Ar pielikumu",
+    "conversations_range": "{from}–{to, number} no {total, number}",
     "conversations_count": "{count} no {total} sarunām",
     "conversations_count_plus": "{count}+ sarunas",
     "conversations_count_simple": "{count} sarunas",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimizēt",
+    "maximize": "Pilnekrāns",
+    "restore": "Atjaunot",
     "read_receipt_on": "Pieprasīts lasīšanas apstiprinājums (noklikšķiniet, lai atspējotu)",
     "read_receipt_off": "Pieprasīt lasīšanas apstiprinājumu",
     "dsn_on": "Piegādes paziņojums pieprasīts (noklikšķiniet, lai atspējotu)",
@@ -1068,6 +1074,12 @@
         "regular": "Parasts",
         "comfortable": "Plašs"
       },
+      "interface_layout": {
+        "label": "Saskarnes izkārtojums",
+        "description": "Kur atrodas meklēšana, navigācija un rīkjoslas",
+        "default": "Noklusējuma",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Iespējot animācijas",
         "description": "Rādīt plūstošas pārejas un efektus"
@@ -2444,7 +2456,8 @@
       "next_email": "Nākamā vēstule",
       "previous_email": "Iepriekšējā vēstule",
       "open_email": "Atvērt vēstuli",
-      "close_email": "Aizvērt / Noņemt atlasi"
+      "close_email": "Aizvērt / Noņemt atlasi",
+      "go_to_folder": "Pāriet uz mapi"
     },
     "actions": {
       "reply": "Atbildēt",
@@ -2466,7 +2479,8 @@
       "global_search": "Meklēt visā"
     },
     "threads": {
-      "expand_collapse": "Izvērst/sairt sarunu"
+      "expand_collapse": "Izvērst/sairt sarunu",
+      "select_mountain_view": "Atlasīt sarunu"
     },
     "composer": {
       "send": "Nosūtīt e-pastu",
diff --git a/locales/mn/common.json b/locales/mn/common.json
index 6a78853fb..8209e65c3 100644
--- a/locales/mn/common.json
+++ b/locales/mn/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Бүгдийг нь харуулах ({count})",
     "show_fewer_tags": "Бага харуулах",
     "folders": "Хавтас",
+    "show_more": "Илүү",
+    "show_fewer": "Бага",
     "shared": "Хуваалцсан",
     "mail": "Мэйл",
     "nav_label": "Навигаци",
@@ -237,6 +239,7 @@
     "replied": "Хариулсан",
     "forwarded": "Дамжуулсан",
     "has_attachment": "Хавсралттай",
+    "conversations_range": "{from}–{to, number} / {total, number}",
     "conversations_count": "{total} харилцан ярианы {count}",
     "conversations_count_plus": "{count}+ харилцан яриа",
     "conversations_count_simple": "{count} харилцан яриа",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Багасгах",
+    "maximize": "Бүтэн дэлгэц",
+    "restore": "Сэргээх",
     "read_receipt_on": "Уншсан баримт хүссэн (идэвхгүй болгохын тулд дарна уу)",
     "read_receipt_off": "Уншсан баримт хүсэх",
     "dsn_on": "Хүргэлтийн мэдэгдэл хүссэн (идэвхгүй болгох бол дарна уу)",
@@ -1071,6 +1077,12 @@
         "regular": "Тогтмол",
         "comfortable": "Тав тухтай"
       },
+      "interface_layout": {
+        "label": "Интерфейсийн байрлал",
+        "description": "Хайлт, навигаци, хэрэгслийн мөр хаана байрлах",
+        "default": "Үндсэн",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Анимацийг идэвхжүүлэх",
         "description": "Гөлгөр шилжилт, эффектийг харуулах"
@@ -2444,7 +2456,8 @@
       "next_email": "Дараагийн имэйл",
       "previous_email": "Өмнөх имэйл",
       "open_email": "Имэйл нээх",
-      "close_email": "Хаах / Сонголтыг цуцлах"
+      "close_email": "Хаах / Сонголтыг цуцлах",
+      "go_to_folder": "Хавтас руу очих"
     },
     "actions": {
       "reply": "Хариулах",
@@ -2466,7 +2479,8 @@
       "global_search": "Бүгдийг хайх"
     },
     "threads": {
-      "expand_collapse": "Хэлхээсийг дэлгэх/хумих"
+      "expand_collapse": "Хэлхээсийг дэлгэх/хумих",
+      "select_mountain_view": "Харилцааг сонгох"
     },
     "composer": {
       "send": "Имэйл илгээх",
diff --git a/locales/nb/common.json b/locales/nb/common.json
index 71041689f..ebd0af43e 100644
--- a/locales/nb/common.json
+++ b/locales/nb/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Vis alle ({count})",
     "show_fewer_tags": "Vis færre",
     "folders": "Mapper",
+    "show_more": "Mer",
+    "show_fewer": "Mindre",
     "shared": "Delt",
     "mail": "E-post",
     "nav_label": "Navigasjon",
@@ -237,6 +239,7 @@
     "replied": "Besvart",
     "forwarded": "Videresendt",
     "has_attachment": "Har vedlegg",
+    "conversations_range": "{from}–{to, number} av {total, number}",
     "conversations_count": "{count} av {total} samtaler",
     "conversations_count_plus": "{count}+ samtaler",
     "conversations_count_simple": "{count} samtaler",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimer",
+    "maximize": "Fullskjerm",
+    "restore": "Gjenopprett",
     "read_receipt_on": "Ber om lesebekreftelse (klikk for å slå av)",
     "read_receipt_off": "Be om lesebekreftelse",
     "dsn_on": "Leveringsvarsel forespurt (klikk for å slå av)",
@@ -1071,6 +1077,12 @@
         "regular": "Vanlig",
         "comfortable": "Luftig"
       },
+      "interface_layout": {
+        "label": "Grensesnittoppsett",
+        "description": "Hvor søk, navigasjon og verktøylinjer ligger",
+        "default": "Standard",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Aktiver animasjoner",
         "description": "Vis jevne overganger og effekter"
@@ -2444,7 +2456,8 @@
       "next_email": "Neste e-post",
       "previous_email": "Forrige e-post",
       "open_email": "Åpne e-post",
-      "close_email": "Lukk / fjern valget"
+      "close_email": "Lukk / fjern valget",
+      "go_to_folder": "Gå til mappe"
     },
     "actions": {
       "reply": "Svar",
@@ -2466,7 +2479,8 @@
       "global_search": "Søk i alt"
     },
     "threads": {
-      "expand_collapse": "Utvid eller fold sammen tråden"
+      "expand_collapse": "Utvid eller fold sammen tråden",
+      "select_mountain_view": "Velg samtalen"
     },
     "composer": {
       "send": "Send e-post",
diff --git a/locales/nl/common.json b/locales/nl/common.json
index f2b8b35f2..a5e356a06 100644
--- a/locales/nl/common.json
+++ b/locales/nl/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Alles tonen ({count})",
     "show_fewer_tags": "Minder tonen",
     "folders": "Mappen",
+    "show_more": "Meer",
+    "show_fewer": "Minder",
     "mail": "E-mail",
     "nav_label": "Navigatie",
     "add_app": "Apps",
@@ -237,6 +239,7 @@
     "replied": "Beantwoord",
     "forwarded": "Doorgestuurd",
     "has_attachment": "Met bijlage",
+    "conversations_range": "{from}–{to, number} van {total, number}",
     "conversations_count": "{count} van {total} gesprekken",
     "conversations_count_plus": "{count}+ gesprekken",
     "conversations_count_simple": "{count} gesprekken",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimaliseren",
+    "maximize": "Volledig scherm",
+    "restore": "Herstellen",
     "read_receipt_on": "Leesbevestiging aangevraagd (klik om uit te schakelen)",
     "read_receipt_off": "Leesbevestiging aanvragen",
     "dsn_on": "Bezorgmelding aangevraagd (klik om uit te schakelen)",
@@ -1068,6 +1074,12 @@
         "regular": "Normaal",
         "comfortable": "Comfortabel"
       },
+      "interface_layout": {
+        "label": "Interface-indeling",
+        "description": "Waar zoeken, navigatie en werkbalken staan",
+        "default": "Standaard",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Animaties inschakelen",
         "description": "Vloeiende overgangen en effecten tonen"
@@ -2444,7 +2456,8 @@
       "next_email": "Volgende e-mail",
       "previous_email": "Vorige e-mail",
       "open_email": "E-mail openen",
-      "close_email": "Sluiten / Deselecteren"
+      "close_email": "Sluiten / Deselecteren",
+      "go_to_folder": "Ga naar map"
     },
     "actions": {
       "reply": "Beantwoorden",
@@ -2466,7 +2479,8 @@
       "global_search": "Alles doorzoeken"
     },
     "threads": {
-      "expand_collapse": "Gesprek uitklappen/inklappen"
+      "expand_collapse": "Gesprek uitklappen/inklappen",
+      "select_mountain_view": "Gesprek selecteren"
     },
     "composer": {
       "send": "E-mail verzenden",
diff --git a/locales/pl/common.json b/locales/pl/common.json
index 5947f1aa4..7867ec259 100644
--- a/locales/pl/common.json
+++ b/locales/pl/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Pokaż wszystkie ({count})",
     "show_fewer_tags": "Pokaż mniej",
     "folders": "Foldery",
+    "show_more": "Więcej",
+    "show_fewer": "Mniej",
     "mail": "Poczta",
     "nav_label": "Nawigacja",
     "add_app": "Aplikacje",
@@ -237,6 +239,7 @@
     "replied": "Odpowiedziano",
     "forwarded": "Przekazano",
     "has_attachment": "Z załącznikiem",
+    "conversations_range": "{from}–{to, number} z {total, number}",
     "conversations_count": "{count} z {total} konwersacji",
     "conversations_count_plus": "{count}+ konwersacji",
     "conversations_count_simple": "{count} konwersacji",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimalizuj",
+    "maximize": "Pełny ekran",
+    "restore": "Przywróć",
     "read_receipt_on": "Zażądano potwierdzenia przeczytania (kliknij, aby wyłączyć)",
     "read_receipt_off": "Zażądaj potwierdzenia przeczytania",
     "dsn_on": "Zażądano powiadomienia o dostarczeniu (kliknij, aby wyłączyć)",
@@ -1068,6 +1074,12 @@
         "regular": "Zwykły",
         "comfortable": "Wygodny"
       },
+      "interface_layout": {
+        "label": "Układ interfejsu",
+        "description": "Gdzie znajdują się wyszukiwarka, nawigacja i paski narzędzi",
+        "default": "Domyślny",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Włącz animacje",
         "description": "Pokazuj płynne przejścia i efekty"
@@ -2444,7 +2456,8 @@
       "next_email": "Następna wiadomość",
       "previous_email": "Poprzednia wiadomość",
       "open_email": "Otwórz wiadomość",
-      "close_email": "Zamknij / Odznacz"
+      "close_email": "Zamknij / Odznacz",
+      "go_to_folder": "Przejdź do folderu"
     },
     "actions": {
       "reply": "Odpowiedz",
@@ -2466,7 +2479,8 @@
       "global_search": "Szukaj wszędzie"
     },
     "threads": {
-      "expand_collapse": "Rozwiń/zwiń wątek"
+      "expand_collapse": "Rozwiń/zwiń wątek",
+      "select_mountain_view": "Zaznacz konwersację"
     },
     "composer": {
       "send": "Wyślij e-mail",
diff --git a/locales/pt/common.json b/locales/pt/common.json
index 5951f05e4..9a697715d 100644
--- a/locales/pt/common.json
+++ b/locales/pt/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Mostrar tudo ({count})",
     "show_fewer_tags": "Mostrar menos",
     "folders": "Pastas",
+    "show_more": "Mais",
+    "show_fewer": "Menos",
     "mail": "E-mail",
     "nav_label": "Navegação",
     "add_app": "Apps",
@@ -237,6 +239,7 @@
     "replied": "Respondido",
     "forwarded": "Encaminhado",
     "has_attachment": "Com anexo",
+    "conversations_range": "{from}–{to, number} de {total, number}",
     "conversations_count": "{count} de {total} conversas",
     "conversations_count_plus": "{count}+ conversas",
     "conversations_count_simple": "{count} conversas",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimizar",
+    "maximize": "Ecrã inteiro",
+    "restore": "Restaurar",
     "read_receipt_on": "Confirmação de leitura solicitada (clique para desativar)",
     "read_receipt_off": "Solicitar confirmação de leitura",
     "dsn_on": "Notificação de entrega pedida (clique para desativar)",
@@ -1068,6 +1074,12 @@
         "regular": "Normal",
         "comfortable": "Confortável"
       },
+      "interface_layout": {
+        "label": "Esquema da interface",
+        "description": "Onde ficam a pesquisa, a navegação e as barras de ferramentas",
+        "default": "Predefinido",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Habilitar Animações",
         "description": "Mostrar transições e efeitos suaves"
@@ -2444,7 +2456,8 @@
       "next_email": "Próximo e-mail",
       "previous_email": "E-mail anterior",
       "open_email": "Abrir e-mail",
-      "close_email": "Fechar / Desselecionar"
+      "close_email": "Fechar / Desselecionar",
+      "go_to_folder": "Ir para a pasta"
     },
     "actions": {
       "reply": "Responder",
@@ -2466,7 +2479,8 @@
       "global_search": "Pesquisar em tudo"
     },
     "threads": {
-      "expand_collapse": "Expandir/recolher conversa"
+      "expand_collapse": "Expandir/recolher conversa",
+      "select_mountain_view": "Selecionar a conversa"
     },
     "composer": {
       "send": "Enviar e-mail",
diff --git a/locales/ro/common.json b/locales/ro/common.json
index cb025d88e..8e5ecd1f4 100644
--- a/locales/ro/common.json
+++ b/locales/ro/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Afișează tot ({count})",
     "show_fewer_tags": "Afișează mai puține",
     "folders": "Dosare",
+    "show_more": "Mai multe",
+    "show_fewer": "Mai puține",
     "shared": "Partajat",
     "mail": "E-mail",
     "nav_label": "Navigare",
@@ -237,6 +239,7 @@
     "replied": "Răspuns",
     "forwarded": "Redirecționat",
     "has_attachment": "Cu atașament",
+    "conversations_range": "{from}–{to, number} din {total, number}",
     "conversations_count": "{count} din conversațiile de pe {total}",
     "conversations_count_plus": "{count}+ conversations",
     "conversations_count_simple": "{count} conversații",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimizează",
+    "maximize": "Ecran complet",
+    "restore": "Restabilește",
     "read_receipt_on": "Solicitare confirmare de citire (faceți clic pentru a dezactiva)",
     "read_receipt_off": "Solicitați o confirmare de citire",
     "dsn_on": "Notificare de livrare solicitată (clic pentru a dezactiva)",
@@ -1071,6 +1077,12 @@
         "regular": "Regulat",
         "comfortable": "Confortabil"
       },
+      "interface_layout": {
+        "label": "Aspectul interfeței",
+        "description": "Unde se află căutarea, navigarea și barele de instrumente",
+        "default": "Implicit",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Activați animațiile",
         "description": "Prezentați tranziții și efecte fluide"
@@ -2444,7 +2456,8 @@
       "next_email": "Următorul e-mail",
       "previous_email": "E-mailul anterior",
       "open_email": "Deschide e-mailul",
-      "close_email": "Închide / Deselectează"
+      "close_email": "Închide / Deselectează",
+      "go_to_folder": "Mergi la dosar"
     },
     "actions": {
       "reply": "Răspunde",
@@ -2466,7 +2479,8 @@
       "global_search": "Caută în tot"
     },
     "threads": {
-      "expand_collapse": "Extindeți/reduceți firul de discuție"
+      "expand_collapse": "Extindeți/reduceți firul de discuție",
+      "select_mountain_view": "Selectează conversația"
     },
     "composer": {
       "send": "Trimite e-mail",
diff --git a/locales/ru/common.json b/locales/ru/common.json
index 7c03e8485..a253c11ec 100644
--- a/locales/ru/common.json
+++ b/locales/ru/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Показать все ({count})",
     "show_fewer_tags": "Показать меньше",
     "folders": "Папки",
+    "show_more": "Ещё",
+    "show_fewer": "Свернуть",
     "mail": "Почта",
     "nav_label": "Навигация",
     "add_app": "Приложения",
@@ -237,6 +239,7 @@
     "replied": "Отвечено",
     "forwarded": "Переслано",
     "has_attachment": "С вложением",
+    "conversations_range": "{from}–{to, number} из {total, number}",
     "conversations_count": "{count} из {total} бесед",
     "conversations_count_plus": "{count}+ бесед",
     "conversations_count_simple": "{count} бесед",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Свернуть",
+    "maximize": "Во весь экран",
+    "restore": "Восстановить",
     "read_receipt_on": "Запрошено уведомление о прочтении (нажмите, чтобы отключить)",
     "read_receipt_off": "Запросить уведомление о прочтении",
     "dsn_on": "Запрошено уведомление о доставке (нажмите, чтобы отключить)",
@@ -1068,6 +1074,12 @@
         "regular": "Обычный",
         "comfortable": "Просторный"
       },
+      "interface_layout": {
+        "label": "Макет интерфейса",
+        "description": "Где находятся поиск, навигация и панели инструментов",
+        "default": "По умолчанию",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Включить анимации",
         "description": "Показывать плавные переходы и эффекты"
@@ -2444,7 +2456,8 @@
       "next_email": "Следующее письмо",
       "previous_email": "Предыдущее письмо",
       "open_email": "Открыть письмо",
-      "close_email": "Закрыть / Отменить выбор"
+      "close_email": "Закрыть / Отменить выбор",
+      "go_to_folder": "Перейти к папке"
     },
     "actions": {
       "reply": "Ответить",
@@ -2466,7 +2479,8 @@
       "global_search": "Искать везде"
     },
     "threads": {
-      "expand_collapse": "Развернуть/свернуть цепочку"
+      "expand_collapse": "Развернуть/свернуть цепочку",
+      "select_mountain_view": "Выбрать переписку"
     },
     "composer": {
       "send": "Отправить письмо",
diff --git a/locales/sk/common.json b/locales/sk/common.json
index 5c978db8e..a97d6cc80 100644
--- a/locales/sk/common.json
+++ b/locales/sk/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Zobraziť všetko ({count})",
     "show_fewer_tags": "Zobraziť menej",
     "folders": "Priečinky",
+    "show_more": "Viac",
+    "show_fewer": "Menej",
     "shared": "Zdieľané",
     "mail": "Pošta",
     "nav_label": "Navigácia",
@@ -237,6 +239,7 @@
     "replied": "Zodpovedané",
     "forwarded": "Preposlané",
     "has_attachment": "Obsahuje prílohu",
+    "conversations_range": "{from}–{to, number} z {total, number}",
     "conversations_count": "{count} z {total} konverzácií",
     "conversations_count_plus": "{count}+ konverzácií",
     "conversations_count_simple": "{count} konverzácií",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Minimalizovať",
+    "maximize": "Celá obrazovka",
+    "restore": "Obnoviť",
     "read_receipt_on": "Potvrdenie o prečítaní požiadané (kliknutím vypnete)",
     "read_receipt_off": "Požiadať o potvrdenie o prečítaní",
     "dsn_on": "Oznámenie o doručení vyžiadané (kliknutím vypnete)",
@@ -1071,6 +1077,12 @@
         "regular": "Bežné",
         "comfortable": "Pohodlné"
       },
+      "interface_layout": {
+        "label": "Rozloženie rozhrania",
+        "description": "Kde sa nachádza hľadanie, navigácia a panely nástrojov",
+        "default": "Predvolené",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Povoliť animácie",
         "description": "Zobrazovať plynulé prechody a efekty"
@@ -2444,7 +2456,8 @@
       "next_email": "Ďalší e-mail",
       "previous_email": "Predchádzajúci e-mail",
       "open_email": "Otvoriť e-mail",
-      "close_email": "Zavrieť / Zrušiť výber"
+      "close_email": "Zavrieť / Zrušiť výber",
+      "go_to_folder": "Prejsť do priečinka"
     },
     "actions": {
       "reply": "Odpovedať",
@@ -2466,7 +2479,8 @@
       "global_search": "Hľadať všade"
     },
     "threads": {
-      "expand_collapse": "Rozbaliť/zbaliť vlákno"
+      "expand_collapse": "Rozbaliť/zbaliť vlákno",
+      "select_mountain_view": "Vybrať konverzáciu"
     },
     "composer": {
       "send": "Odoslať e-mail",
diff --git a/locales/tr/common.json b/locales/tr/common.json
index 6aaefc6b9..6b6e8cc3e 100644
--- a/locales/tr/common.json
+++ b/locales/tr/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Tümünü göster ({count})",
     "show_fewer_tags": "Daha az göster",
     "folders": "Klasörler",
+    "show_more": "Diğer",
+    "show_fewer": "Daha az",
     "shared": "Paylaşılan",
     "mail": "Posta",
     "nav_label": "Gezinme",
@@ -237,6 +239,7 @@
     "replied": "Yanıtlandı",
     "forwarded": "İletildi",
     "has_attachment": "Ek içeriyor",
+    "conversations_range": "{total, number} içinde {from}–{to, number}",
     "conversations_count": "{total} konuşmadan {count} tanesi",
     "conversations_count_plus": "{count}+ konuşma",
     "conversations_count_simple": "{count} konuşma",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Simge durumuna küçült",
+    "maximize": "Tam ekran",
+    "restore": "Geri yükle",
     "read_receipt_on": "Okundu bilgisi istendi (devre dışı bırakmak için tıklayın)",
     "read_receipt_off": "Okundu bilgisi iste",
     "dsn_on": "Teslimat bildirimi istendi (kapatmak için tıklayın)",
@@ -1068,6 +1074,12 @@
         "regular": "Normal",
         "comfortable": "Rahat"
       },
+      "interface_layout": {
+        "label": "Arayüz düzeni",
+        "description": "Arama, gezinme ve araç çubuklarının konumu",
+        "default": "Varsayılan",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Animasyonları Etkinleştir",
         "description": "Akıcı geçişler ve efektler göster"
@@ -2444,7 +2456,8 @@
       "next_email": "Sonraki e-posta",
       "previous_email": "Önceki e-posta",
       "open_email": "E-postayı aç",
-      "close_email": "Kapat / Seçimi kaldır"
+      "close_email": "Kapat / Seçimi kaldır",
+      "go_to_folder": "Klasöre git"
     },
     "actions": {
       "reply": "Yanıtla",
@@ -2466,7 +2479,8 @@
       "global_search": "Her yerde ara"
     },
     "threads": {
-      "expand_collapse": "İleti dizisini genişlet/daralt"
+      "expand_collapse": "İleti dizisini genişlet/daralt",
+      "select_mountain_view": "Konuşmayı seç"
     },
     "composer": {
       "send": "E-posta gönder",
diff --git a/locales/uk/common.json b/locales/uk/common.json
index 7859ac4b1..0939b5cd0 100644
--- a/locales/uk/common.json
+++ b/locales/uk/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "Показати всі ({count})",
     "show_fewer_tags": "Показати менше",
     "folders": "Папки",
+    "show_more": "Більше",
+    "show_fewer": "Менше",
     "mail": "Пошта",
     "nav_label": "Навігація",
     "add_app": "програми",
@@ -237,6 +239,7 @@
     "replied": "Відповіли",
     "forwarded": "Переслано",
     "has_attachment": "З вкладенням",
+    "conversations_range": "{from}–{to, number} з {total, number}",
     "conversations_count": "{count} з {total} розмов",
     "conversations_count_plus": "{count}+ розмов",
     "conversations_count_simple": "{count} розмов",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "Згорнути",
+    "maximize": "На весь екран",
+    "restore": "Відновити",
     "read_receipt_on": "Запитано сповіщення про прочитання (натисніть, щоб вимкнути)",
     "read_receipt_off": "Запитати сповіщення про прочитання",
     "dsn_on": "Запитано сповіщення про доставку (натисніть, щоб вимкнути)",
@@ -1068,6 +1074,12 @@
         "regular": "Регулярний",
         "comfortable": "Комфортно"
       },
+      "interface_layout": {
+        "label": "Макет інтерфейсу",
+        "description": "Де розташовані пошук, навігація та панелі інструментів",
+        "default": "За замовчуванням",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "Увімкнути анімацію",
         "description": "Показувати плавні переходи та ефекти"
@@ -2444,7 +2456,8 @@
       "next_email": "Наступний електронний лист",
       "previous_email": "Попередній електронний лист",
       "open_email": "Відкрийте електронну пошту",
-      "close_email": "Закрити / Скасувати вибір"
+      "close_email": "Закрити / Скасувати вибір",
+      "go_to_folder": "Перейти до теки"
     },
     "actions": {
       "reply": "Відповісти",
@@ -2466,7 +2479,8 @@
       "global_search": "Шукати скрізь"
     },
     "threads": {
-      "expand_collapse": "Розгорнути/згорнути ланцюжок"
+      "expand_collapse": "Розгорнути/згорнути ланцюжок",
+      "select_mountain_view": "Вибрати листування"
     },
     "composer": {
       "send": "Надіслати лист",
diff --git a/locales/zh-TW/common.json b/locales/zh-TW/common.json
index 0e9d6dc1c..91f310229 100644
--- a/locales/zh-TW/common.json
+++ b/locales/zh-TW/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "顯示全部（{count}）",
     "show_fewer_tags": "顯示較少",
     "folders": "信件匣",
+    "show_more": "更多",
+    "show_fewer": "收合",
     "shared": "共用",
     "mail": "郵件",
     "nav_label": "導覽",
@@ -237,6 +239,7 @@
     "replied": "已回覆",
     "forwarded": "已轉寄",
     "has_attachment": "有附件",
+    "conversations_range": "第 {from}–{to, number} 封，共 {total, number} 封",
     "conversations_count": "顯示 {count} 個對話串，共 {total} 個",
     "conversations_count_plus": "{count}+ 個對話串",
     "conversations_count_simple": "{count} 個對話串",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "最小化",
+    "maximize": "全螢幕",
+    "restore": "還原",
     "read_receipt_on": "已要求傳送已讀回執（點擊以停用）",
     "read_receipt_off": "請求已讀回執",
     "dsn_on": "已要求遞送通知（點擊停用）",
@@ -1071,6 +1077,12 @@
         "regular": "預設",
         "comfortable": "寬鬆"
       },
+      "interface_layout": {
+        "label": "介面版面配置",
+        "description": "搜尋、導覽與工具列的位置",
+        "default": "預設",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "啟用動畫",
         "description": "顯示平順的轉場與效果"
@@ -2444,7 +2456,8 @@
       "next_email": "下一封郵件",
       "previous_email": "上一封郵件",
       "open_email": "開啟郵件",
-      "close_email": "關閉／取消選取"
+      "close_email": "關閉／取消選取",
+      "go_to_folder": "跳至資料夾"
     },
     "actions": {
       "reply": "回覆",
@@ -2466,7 +2479,8 @@
       "global_search": "全域搜尋"
     },
     "threads": {
-      "expand_collapse": "展開／收合對話串"
+      "expand_collapse": "展開／收合對話串",
+      "select_mountain_view": "選取會話"
     },
     "composer": {
       "send": "傳送郵件",
diff --git a/locales/zh/common.json b/locales/zh/common.json
index f43ec5e65..917228c7e 100644
--- a/locales/zh/common.json
+++ b/locales/zh/common.json
@@ -142,6 +142,8 @@
     "show_all_tags": "显示全部（{count}）",
     "show_fewer_tags": "收起",
     "folders": "文件夹",
+    "show_more": "更多",
+    "show_fewer": "收起",
     "mail": "邮件",
     "nav_label": "导航",
     "add_app": "应用",
@@ -237,6 +239,7 @@
     "replied": "已回复",
     "forwarded": "已转发",
     "has_attachment": "有附件",
+    "conversations_range": "第 {from}–{to, number} 个，共 {total, number} 个",
     "conversations_count": "共 {total} 个会话，当前显示 {count} 个",
     "conversations_count_plus": "{count}+ 个会话",
     "conversations_count_simple": "{count} 个会话",
@@ -597,6 +600,9 @@
     }
   },
   "email_composer": {
+    "minimize": "最小化",
+    "maximize": "全屏",
+    "restore": "还原",
     "read_receipt_on": "已请求已读回执（点击以关闭）",
     "read_receipt_off": "请求已读回执",
     "dsn_on": "已请求投递通知（点击禁用）",
@@ -1068,6 +1074,12 @@
         "regular": "默认",
         "comfortable": "宽松"
       },
+      "interface_layout": {
+        "label": "界面布局",
+        "description": "搜索、导航和工具栏的位置",
+        "default": "默认",
+        "mountain_view": "Mountain View"
+      },
       "animations": {
         "label": "启用动画",
         "description": "显示平滑的过渡和效果"
@@ -2444,7 +2456,8 @@
       "next_email": "下一封邮件",
       "previous_email": "上一封邮件",
       "open_email": "打开邮件",
-      "close_email": "关闭/取消选择"
+      "close_email": "关闭/取消选择",
+      "go_to_folder": "跳转到文件夹"
     },
     "actions": {
       "reply": "回复",
@@ -2466,7 +2479,8 @@
       "global_search": "全局搜索"
     },
     "threads": {
-      "expand_collapse": "展开/折叠会话"
+      "expand_collapse": "展开/折叠会话",
+      "select_mountain_view": "选择会话"
     },
     "composer": {
       "send": "发送邮件",
diff --git a/scripts/mountain-view-smoke/mountain-view-smoke.mjs b/scripts/mountain-view-smoke/mountain-view-smoke.mjs
new file mode 100644
index 000000000..78226b13a
--- /dev/null
+++ b/scripts/mountain-view-smoke/mountain-view-smoke.mjs
@@ -0,0 +1,131 @@
+#!/usr/bin/env node
+/**
+ * Smoke test for Mountain View, run against a live instance.
+ *
+ * The integration suite (integration/) needs Docker for its Stalwart stack;
+ * this one only needs a running webmail and one mailbox with some mail in it:
+ *
+ *   MV_URL=http://127.0.0.1:3000 MV_USER=me@example.com MV_PASS=... \
+ *     node scripts/mountain-view-smoke/mountain-view-smoke.mjs
+ *
+ * MV_SERVER optionally picks the login form's server entry by id. The
+ * password is read from the environment only and never printed. It turns
+ * Mountain View on in a fresh browser profile, then checks the layout's own
+ * structure - not the mail in the box - on a desktop and a phone viewport.
+ * It exits non-zero if any check failed.
+ */
+/* global document */
+import { chromium } from 'playwright';
+
+const url = (process.env.MV_URL || '').replace(/\/+$/, '');
+const user = process.env.MV_USER;
+const pass = process.env.MV_PASS;
+if (!url || !user || !pass) {
+  console.error('Set MV_URL, MV_USER and MV_PASS.');
+  process.exit(2);
+}
+
+const results = [];
+const check = (name, ok, detail = '') => {
+  results.push({ name, ok });
+  console.log(`${ok ? 'ok  ' : 'FAIL'} ${name}${detail ? ` - ${detail}` : ''}`);
+};
+
+async function signIn(context) {
+  // The layout is a stored setting: put it in place before the app reads its
+  // storage. The version matches the settings store's, so nothing migrates it.
+  await context.addInitScript(() => {
+    if (!localStorage.getItem('settings-storage')) {
+      localStorage.setItem('settings-storage', JSON.stringify({ state: { interfaceLayout: 'mountain-view' }, version: 7 }));
+    }
+  });
+  const page = await context.newPage();
+  const errors = [];
+  page.on('pageerror', (e) => errors.push(e.message));
+  await page.goto(`${url}/en/login`, { waitUntil: 'networkidle' });
+  if (process.env.MV_SERVER && await page.locator('#jmap-server-select').count()) {
+    await page.selectOption('#jmap-server-select', process.env.MV_SERVER);
+  }
+  await page.fill('input[type=email], input[name=username], #username', user);
+  await page.fill('input[type=password]', pass);
+  await page.click('button[type=submit]');
+  await page.waitForURL(/\/mail/, { timeout: 60_000 });
+  await page.locator('[data-email-id]').first().waitFor({ timeout: 60_000 });
+  return { page, errors };
+}
+
+async function desktop(browser) {
+  const context = await browser.newContext({ viewport: { width: 1440, height: 900 } });
+  const { page, errors } = await signIn(context);
+
+  check('desktop: Mountain View is applied', await page.evaluate(() => document.documentElement.dataset.interfaceLayout === 'mountain-view'));
+  check('desktop: Starred sits right under the Inbox', await page.evaluate(() => {
+    const rows = [...document.querySelectorAll('[data-folder-name], [data-folder-role]')]
+      .map((r) => r.getAttribute('data-folder-name') || r.getAttribute('data-folder-role'));
+    const inbox = rows.indexOf('inbox') >= 0 ? rows.indexOf('inbox') : rows.findIndex((r) => /inbox/i.test(r || ''));
+    return inbox >= 0 && rows[inbox + 1] === 'mv-starred';
+  }));
+  const range = await page.getByText(/^\s*1–\d/).first().textContent().catch(() => null);
+  check('desktop: list toolbar shows a 1–N range', !!range && /1–\d/.test(range), range?.trim() ?? '');
+  check('desktop: search options button sits inside the field', await page.evaluate(() => {
+    const field = document.querySelector('.mv-topbar input[data-search-input]');
+    const btn = document.querySelector('.mv-topbar-search > button');
+    if (!field || !btn) return false;
+    const f = field.getBoundingClientRect();
+    const b = btn.getBoundingClientRect();
+    return b.left >= f.left && b.right <= f.right + 1;
+  }));
+
+  await page.locator('[data-email-id]').first().click();
+  await page.locator('[data-mv-sender-date]').first().waitFor({ timeout: 30_000 }).catch(() => {});
+  check('desktop: message date sits on the sender line', await page.locator('[data-mv-sender-date]').count() > 0);
+  await page.locator('[data-mv-reply-row]').waitFor({ timeout: 30_000 }).catch(() => {});
+  check('desktop: Reply / Reply all / Forward under the message', await page.locator('[data-mv-reply-row] button').count() === 3);
+  await page.keyboard.press('Escape');
+
+  await page.locator('[data-mv-compose]').first().click();
+  const win = page.locator('[data-mv-compose-window]');
+  await win.waitFor({ timeout: 20_000 }).catch(() => {});
+  check('desktop: compose opens a docked window', await win.count() === 1);
+  if (await win.count()) {
+    const box = await win.boundingBox();
+    check('desktop: compose window is docked bottom-right', !!box && box.x > 600 && box.y + box.height >= 899 - 2);
+    await win.locator('button[aria-label]').first().click();
+    await page.waitForTimeout(400);
+    check('desktop: compose window folds to its title bar', (await win.getAttribute('data-state')) === 'minimized');
+  }
+  check('desktop: no page errors', errors.length === 0, errors[0] ?? '');
+  await context.close();
+}
+
+async function phone(browser) {
+  const context = await browser.newContext({
+    viewport: { width: 412, height: 915 }, isMobile: true, hasTouch: true, deviceScaleFactor: 2,
+    userAgent: 'Mozilla/5.0 (Linux; Android 14; Pixel 8) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Mobile Safari/537.36',
+  });
+  const { page, errors } = await signIn(context);
+  check('phone: rows are Mountain View phone rows', await page.locator('[data-mv-mobile-row]').count() > 0);
+  check('phone: one star per row, on the preview line', await page.evaluate(() => {
+    const row = document.querySelector('[data-mv-mobile-row]');
+    if (!row) return false;
+    const stars = row.querySelectorAll('button[aria-pressed]');
+    return stars.length === 1 && !!stars[0].parentElement?.querySelector('p');
+  }));
+  await page.locator('[data-email-id]').first().click();
+  await page.locator('[data-mv-reply-row]').waitFor({ timeout: 30_000 }).catch(() => {});
+  check('phone: the message ends with Reply / Reply all / Forward', await page.locator('[data-mv-reply-row] button').count() === 3);
+  check('phone: no bottom bar over the message', await page.locator('nav.fixed.bottom-0').count() === 0);
+  check('phone: no page errors', errors.length === 0, errors[0] ?? '');
+  await context.close();
+}
+
+const browser = await chromium.launch();
+try {
+  await desktop(browser);
+  await phone(browser);
+} finally {
+  await browser.close();
+}
+const failed = results.filter((r) => !r.ok).length;
+console.log(`\n${results.length - failed}/${results.length} checks passed`);
+process.exit(failed ? 1 : 0);
diff --git a/stores/__tests__/settings-density-mountain-view.test.ts b/stores/__tests__/settings-density-mountain-view.test.ts
new file mode 100644
index 000000000..da76a9d08
--- /dev/null
+++ b/stores/__tests__/settings-density-mountain-view.test.ts
@@ -0,0 +1,43 @@
+import { describe, it, expect } from 'vitest';
+import { densityVarsFor, type Density, type InterfaceLayout } from '@/stores/settings-store';
+
+// Mountain View has three row rhythms of its own and the app has four
+// densities. The four are laid over its scale rather than left meaning
+// whatever they meant in the default layout.
+
+const px = (value: string) => Number.parseInt(value, 10);
+const ROW = (density: Density, layout: InterfaceLayout) =>
+  px(densityVarsFor(density, layout)['--list-item-height']);
+
+describe('densityVarsFor', () => {
+  it('lands the three shared names on the 32 / 40 / 48 pixel rows', () => {
+    expect(ROW('compact', 'mountain-view')).toBe(32);
+    expect(ROW('regular', 'mountain-view')).toBe(40);
+    expect(ROW('comfortable', 'mountain-view')).toBe(48);
+  });
+
+  it('continues the series below compact rather than dropping a choice', () => {
+    expect(ROW('extra-compact', 'mountain-view')).toBeLessThan(ROW('compact', 'mountain-view'));
+  });
+
+  it('keeps every step distinct, so all four settings still do something', () => {
+    const heights = (['extra-compact', 'compact', 'regular', 'comfortable'] as Density[])
+      .map((density) => ROW(density, 'mountain-view'));
+    expect(new Set(heights).size).toBe(4);
+    expect([...heights]).toEqual([...heights].sort((a, b) => a - b));
+  });
+
+  it('leaves the default layout exactly as it was', () => {
+    expect(densityVarsFor('regular', 'default')['--list-item-height']).toBe('48px');
+    expect(densityVarsFor('compact', 'default')['--list-item-height']).toBe('auto');
+    expect(densityVarsFor('extra-compact', 'default')['--density-item-py']).toBe('2px');
+  });
+
+  it('restates only the vertical rhythm, not the rest of the spacing', () => {
+    const mountainView = densityVarsFor('regular', 'mountain-view');
+    const standard = densityVarsFor('regular', 'default');
+    expect(mountainView['--density-card-p']).toBe(standard['--density-card-p']);
+    expect(mountainView['--density-sidebar-py']).toBe(standard['--density-sidebar-py']);
+    expect(mountainView['--density-item-py']).not.toBe(standard['--density-item-py']);
+  });
+});
diff --git a/stores/settings-store.ts b/stores/settings-store.ts
index 33df6a566..1a4dc2da9 100644
--- a/stores/settings-store.ts
+++ b/stores/settings-store.ts
@@ -97,6 +97,13 @@ async function syncSettingsJob(job: SettingsSyncJob, retries = 1): Promise<void>
 
 export type FontSize = 'small' | 'medium' | 'large';
 export type Density = 'extra-compact' | 'compact' | 'regular' | 'comfortable';
+/**
+ * Which interface layout drives the shell's geometry. `default` is the app's
+ * own layout; `mountain-view` is an optional alternative arrangement of the
+ * chrome (search-first top bar, flat 256px navigation rail, pill Compose,
+ * docked compose window) that keeps the theme's icons, type and palette.
+ */
+export type InterfaceLayout = 'default' | 'mountain-view';
 /** @deprecated Use Density instead */
 export type ListDensity = Density;
 export type DeleteAction = 'trash' | 'trash-and-read' | 'permanent';
@@ -125,6 +132,23 @@ export type ToolbarPosition = 'top' | 'below-subject';
 export type ArchiveMode = 'single' | 'year' | 'month';
 export type MailLayout = 'split' | 'focus' | 'horizontal';
 
+/**
+ * The mail layout the mail view actually uses.
+ *
+ * Mountain View shows the list at full width and opens a conversation in its
+ * place, which is the `focus` layout. Rather than writing `focus` into the
+ * user's saved `mailLayout`, the layout in force is derived: `focus` under
+ * Mountain View, the saved value otherwise. Switching back to the default
+ * layout therefore restores whatever the user had chosen.
+ *
+ * Read the layout through this (or `useEffectiveMailLayout`) wherever it
+ * decides what is drawn; read `mailLayout` itself only where the saved
+ * preference is being shown or edited.
+ */
+export function effectiveMailLayout(mailLayout: MailLayout, interfaceLayout: InterfaceLayout): MailLayout {
+  return interfaceLayout === 'mountain-view' ? 'focus' : mailLayout;
+}
+
 /**
  * Spacing around a message body in the reader.
  * - 'auto'  : add a gutter unless the email paints its own full-bleed background
@@ -304,6 +328,7 @@ interface SettingsState {
   // Appearance
   fontSize: FontSize;
   density: Density;
+  interfaceLayout: InterfaceLayout;
   animationsEnabled: boolean;
   // Message-list ordering (#718): prioritised sort levels mapped onto the JMAP
   // Email/query sort; empty = chronological. Scope: Inbox only or every folder.
@@ -564,6 +589,7 @@ const DEFAULT_SETTINGS = {
   // Appearance
   fontSize: 'medium' as FontSize,
   density: 'regular' as Density,
+  interfaceLayout: 'default' as InterfaceLayout,
   animationsEnabled: true,
   messageListOrder: [] as SortLevel[],
   messageListOrderScope: 'inbox' as MessageListOrderScope,
@@ -785,7 +811,13 @@ export const useSettingsStore = create<SettingsState>()(
 
         // Apply density to document root
         if (key === 'density') {
-          applyDensity(value as Density);
+          applyDensity(value as Density, get().interfaceLayout);
+        }
+
+        // Swap the shell geometry. Mountain View's list-then-conversation
+        // layout is not written into `mailLayout`: see effectiveMailLayout().
+        if (key === 'interfaceLayout') {
+          applyInterfaceLayout(value as InterfaceLayout, get().density);
         }
 
         // Apply animations to document root
@@ -797,7 +829,8 @@ export const useSettingsStore = create<SettingsState>()(
       resetToDefaults: () => {
         set(DEFAULT_SETTINGS);
         applyFontSize(DEFAULT_SETTINGS.fontSize);
-        applyDensity(DEFAULT_SETTINGS.density);
+        applyDensity(DEFAULT_SETTINGS.density, DEFAULT_SETTINGS.interfaceLayout);
+        applyInterfaceLayout(DEFAULT_SETTINGS.interfaceLayout, DEFAULT_SETTINGS.density);
         applyAnimations(DEFAULT_SETTINGS.animationsEnabled);
       },
 
@@ -807,6 +840,7 @@ export const useSettingsStore = create<SettingsState>()(
         const settings = {
           fontSize: state.fontSize,
           density: state.density,
+          interfaceLayout: state.interfaceLayout,
           animationsEnabled: state.animationsEnabled,
           messageListOrder: state.messageListOrder,
           messageListOrderScope: state.messageListOrderScope,
@@ -1004,7 +1038,8 @@ export const useSettingsStore = create<SettingsState>()(
 
           // Apply visual settings
           applyFontSize(get().fontSize);
-          applyDensity(get().density);
+          applyDensity(get().density, get().interfaceLayout);
+          applyInterfaceLayout(get().interfaceLayout, get().density);
           applyAnimations(get().animationsEnabled);
 
           // Apply cross-store settings
@@ -1234,7 +1269,8 @@ export const useSettingsStore = create<SettingsState>()(
               state.messageListOrderScope = 'inbox';
             }
             applyFontSize(state.fontSize);
-            applyDensity(state.density);
+            applyDensity(state.density, state.interfaceLayout);
+            applyInterfaceLayout(state.interfaceLayout, state.density);
             applyAnimations(state.animationsEnabled);
           }
         };
@@ -1322,52 +1358,87 @@ function applyFontSize(size: FontSize) {
   root.style.setProperty('--font-size-base', sizeMap[size]);
 }
 
-function applyDensity(density: Density) {
+type DensityVars = Record<string, string>;
+
+const DEFAULT_DENSITY: Record<Density, DensityVars> = {
+  'extra-compact': {
+    '--list-item-height': 'auto',
+    '--density-item-py': '2px',
+    '--density-item-gap': '6px',
+    '--density-header-py': '4px',
+    '--density-card-p': '8px',
+    '--density-sidebar-py': '0px',
+  },
+  compact: {
+    '--list-item-height': 'auto',
+    '--density-item-py': '4px',
+    '--density-item-gap': '8px',
+    '--density-header-py': '6px',
+    '--density-card-p': '10px',
+    '--density-sidebar-py': '1px',
+  },
+  regular: {
+    '--list-item-height': '48px',
+    '--density-item-py': '12px',
+    '--density-item-gap': '12px',
+    '--density-header-py': '12px',
+    '--density-card-p': '16px',
+    '--density-sidebar-py': '4px',
+  },
+  comfortable: {
+    '--list-item-height': '64px',
+    '--density-item-py': '16px',
+    '--density-item-gap': '16px',
+    '--density-header-py': '16px',
+    '--density-card-p': '20px',
+    '--density-sidebar-py': '6px',
+  },
+};
+
+/**
+ * Mountain View's rows come in three rhythms - 32, 40 and 48 pixels - and the
+ * app offers four densities. The four are laid over that scale: `compact`,
+ * `regular` and `comfortable` land on the three exactly, and `extra-compact`
+ * continues the series a step below, so every density still does something.
+ *
+ * Only the vertical rhythm is restated. Everything else a density touches -
+ * gaps, card padding, the sidebar's own row padding - keeps its default value;
+ * a navigation row is already pinned to 32px by the layout's own token.
+ */
+const MOUNTAIN_VIEW_DENSITY: Record<Density, DensityVars> = {
+  'extra-compact': { ...DEFAULT_DENSITY['extra-compact'], '--list-item-height': '28px', '--density-item-py': '4px' },
+  compact: { ...DEFAULT_DENSITY.compact, '--list-item-height': '32px', '--density-item-py': '6px' },
+  regular: { ...DEFAULT_DENSITY.regular, '--list-item-height': '40px', '--density-item-py': '10px' },
+  comfortable: { ...DEFAULT_DENSITY.comfortable, '--list-item-height': '48px', '--density-item-py': '14px' },
+};
+
+export function densityVarsFor(density: Density, layout: InterfaceLayout): DensityVars {
+  return (layout === 'mountain-view' ? MOUNTAIN_VIEW_DENSITY : DEFAULT_DENSITY)[density];
+}
+
+function applyDensity(density: Density, layout: InterfaceLayout) {
   if (typeof document === 'undefined') return;
 
   const root = document.documentElement;
-
-  const densityValues = {
-    'extra-compact': {
-      '--list-item-height': 'auto',
-      '--density-item-py': '2px',
-      '--density-item-gap': '6px',
-      '--density-header-py': '4px',
-      '--density-card-p': '8px',
-      '--density-sidebar-py': '0px',
-    },
-    compact: {
-      '--list-item-height': 'auto',
-      '--density-item-py': '4px',
-      '--density-item-gap': '8px',
-      '--density-header-py': '6px',
-      '--density-card-p': '10px',
-      '--density-sidebar-py': '1px',
-    },
-    regular: {
-      '--list-item-height': '48px',
-      '--density-item-py': '12px',
-      '--density-item-gap': '12px',
-      '--density-header-py': '12px',
-      '--density-card-p': '16px',
-      '--density-sidebar-py': '4px',
-    },
-    comfortable: {
-      '--list-item-height': '64px',
-      '--density-item-py': '16px',
-      '--density-item-gap': '16px',
-      '--density-header-py': '16px',
-      '--density-card-p': '20px',
-      '--density-sidebar-py': '6px',
-    },
-  };
-
-  const values = densityValues[density];
-  for (const [prop, val] of Object.entries(values)) {
+  for (const [prop, val] of Object.entries(densityVarsFor(density, layout))) {
     root.style.setProperty(prop, val);
   }
 }
 
+/**
+ * The interface layout is a single attribute on <html>; every geometry
+ * override lives in the `[data-interface-layout="mountain-view"]` block in
+ * globals.css, so nothing has to re-render for the shell to change shape.
+ */
+function applyInterfaceLayout(layout: InterfaceLayout, density: Density) {
+  if (typeof document === 'undefined') return;
+  document.documentElement.dataset.interfaceLayout = layout;
+  // The row rhythm depends on the layout as much as on the density, and it is
+  // written as an inline custom property, which no stylesheet rule could
+  // override. Re-applying it here is what keeps the two in step.
+  applyDensity(density, layout);
+}
+
 function applyAnimations(enabled: boolean) {
   if (typeof document === 'undefined') return;
 
@@ -1383,7 +1454,8 @@ function applyAnimations(enabled: boolean) {
 if (typeof window !== 'undefined') {
   const store = useSettingsStore.getState();
   applyFontSize(store.fontSize);
-  applyDensity(store.density);
+  applyDensity(store.density, store.interfaceLayout);
+  applyInterfaceLayout(store.interfaceLayout, store.density);
   applyAnimations(store.animationsEnabled);
 
   const triggerSync = () => {

From 250df2bb61ffedf0368e46933d7c471454a8553e Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Thu, 8 Oct 2026 08:01:56 +0200
Subject: [PATCH 08/23] perf(mail): open a visited folder at once and load it
 behind its rows

Switching folders kept the previous folder's mail under a spinner until
the new page arrived, and a failed load emptied the folder.

The store now remembers the first page of each plain folder it showed
(in memory, 30 folders, keyed by login, shared owner, folder, category
filter and sort). Opening a remembered folder paints those rows straight
away and fetches in the background; the fresh page replaces them, and a
failure leaves them up with the error. What happens to the list on screen
- a message read, archived, deleted - is remembered with it.
---
 lib/folder-list-cache.ts                      |  68 +++++++
 .../email-store-folder-list-cache.test.ts     | 175 ++++++++++++++++++
 stores/email-store.ts                         |  68 ++++++-
 3 files changed, 310 insertions(+), 1 deletion(-)
 create mode 100644 lib/folder-list-cache.ts
 create mode 100644 stores/__tests__/email-store-folder-list-cache.test.ts

diff --git a/lib/folder-list-cache.ts b/lib/folder-list-cache.ts
new file mode 100644
index 000000000..48312c648
--- /dev/null
+++ b/lib/folder-list-cache.ts
@@ -0,0 +1,68 @@
+import type { Email } from '@/lib/jmap/types';
+
+/**
+ * The last list seen in each folder, so opening a folder paints the rows it
+ * had a moment ago while the fresh page loads behind them - and keeps them if
+ * that load fails. On a slow server or a large folder the difference is an
+ * instant folder against seconds of the previous folder's mail under a
+ * spinner.
+ *
+ * In memory only: mail does not outlive the tab here, unlike the one-list boot
+ * snapshot in the email store, and the live fetch always runs.
+ */
+export interface FolderList {
+  emails: Email[];
+  totalEmails: number;
+  hasMoreEmails: boolean;
+}
+
+/** Folders remembered per tab; the oldest visited is dropped first. */
+const MAX_FOLDERS = 30;
+
+const lists = new Map<string, FolderList>();
+
+/**
+ * What a remembered list belongs to. Folder ids repeat across accounts and
+ * servers, and a category tab or another sort
+ * order is another list of the same folder.
+ */
+export function folderListKey(parts: {
+  login: string | null;
+  viewingAccountId: string | null;
+  accountId: string;
+  mailboxId: string;
+  filter: unknown;
+  order: unknown;
+}): string {
+  return JSON.stringify([
+    parts.login ?? '',
+    parts.viewingAccountId ?? '',
+    parts.accountId,
+    parts.mailboxId,
+    parts.filter ?? null,
+    parts.order ?? null,
+  ]);
+}
+
+export function rememberedFolderList(key: string): FolderList | undefined {
+  return lists.get(key);
+}
+
+export function rememberFolderList(key: string, list: FolderList, pageSize: number): void {
+  lists.delete(key);
+  lists.set(key, {
+    // One page is what a folder opens on; load-more fetches the rest again.
+    emails: list.emails.slice(0, pageSize),
+    totalEmails: list.totalEmails,
+    hasMoreEmails: list.hasMoreEmails || list.emails.length > pageSize,
+  });
+  while (lists.size > MAX_FOLDERS) {
+    const oldest = lists.keys().next().value;
+    if (oldest === undefined) break;
+    lists.delete(oldest);
+  }
+}
+
+export function forgetFolderLists(): void {
+  lists.clear();
+}
diff --git a/stores/__tests__/email-store-folder-list-cache.test.ts b/stores/__tests__/email-store-folder-list-cache.test.ts
new file mode 100644
index 000000000..dbf38bd1b
--- /dev/null
+++ b/stores/__tests__/email-store-folder-list-cache.test.ts
@@ -0,0 +1,175 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { useEmailStore } from '../email-store';
+import { useSettingsStore } from '../settings-store';
+import { forgetFolderLists } from '@/lib/folder-list-cache';
+import type { Email, Mailbox } from '@/lib/jmap/types';
+import type { IJMAPClient } from '@/lib/jmap/client-interface';
+
+/**
+ * Opening a folder paints the rows it showed last time and loads the fresh
+ * page behind them, so a slow server does
+ * not hold the previous folder's mail under a spinner - and a failed load
+ * does not empty a folder that had mail a moment ago.
+ */
+
+const makeEmail = (id: string, extra: Partial<Email> = {}): Email =>
+  ({
+    id,
+    threadId: `t-${id}`,
+    mailboxIds: { inbox: true },
+    keywords: {},
+    from: [{ email: 'a@example.com' }],
+    to: [{ email: 'b@example.com' }],
+    subject: `mail ${id}`,
+    receivedAt: '2026-10-08T10:00:00Z',
+    preview: '',
+    hasAttachment: false,
+    size: 1,
+    ...extra,
+  }) as unknown as Email;
+
+const folder = (id: string, role: string | null) =>
+  ({
+    id,
+    originalId: id,
+    name: id,
+    role,
+    accountId: 'acc',
+    totalEmails: 2,
+    unreadEmails: 0,
+    totalThreads: 2,
+    unreadThreads: 0,
+    sortOrder: 0,
+    isSubscribed: true,
+    myRights: {},
+  }) as unknown as Mailbox;
+
+type Page = { emails: Email[]; hasMore: boolean; total: number; state?: string };
+
+function makeClient(pages: Record<string, () => Promise<Page>>) {
+  const getEmails = vi.fn((mailboxId: string) => pages[mailboxId]());
+  return {
+    client: {
+      getEmails,
+      getAccountId: () => 'acc',
+      getThreadEmails: vi.fn(async () => []),
+    } as unknown as IJMAPClient,
+    getEmails,
+  };
+}
+
+function deferred<T>() {
+  let resolve!: (value: T) => void;
+  let reject!: (error: unknown) => void;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return { promise, resolve, reject };
+}
+
+const ids = () => useEmailStore.getState().emails.map((e) => e.id);
+
+async function open(client: IJMAPClient, mailboxId: string) {
+  useEmailStore.getState().selectMailbox(mailboxId);
+  return useEmailStore.getState().fetchEmails(client, mailboxId);
+}
+
+describe('remembered folder lists', () => {
+  beforeEach(() => {
+    forgetFolderLists();
+    useSettingsStore.setState({ emailsPerPage: 50 });
+    useEmailStore.setState({
+      selectedMailbox: 'inbox',
+      mailboxes: [folder('inbox', 'inbox'), folder('work', null)],
+      accountMailboxes: {},
+      viewingAccountId: null,
+      emails: [],
+      totalEmails: 0,
+      hasMoreEmails: false,
+      emailListSync: null,
+      isUnifiedView: false,
+      isScheduledView: false,
+      selectedKeyword: null,
+      searchQuery: '',
+      isLoading: false,
+      error: null,
+    });
+  });
+
+  it('paints a visited folder at once and replaces it when the fresh page lands', async () => {
+    const fresh = deferred<Page>();
+    let inboxCalls = 0;
+    const { client } = makeClient({
+      inbox: () =>
+        ++inboxCalls === 1
+          ? Promise.resolve({ emails: [makeEmail('a'), makeEmail('b')], hasMore: false, total: 2, state: 's1' })
+          : fresh.promise,
+      work: async () => ({ emails: [makeEmail('w')], hasMore: false, total: 1, state: 's1' }),
+    });
+
+    await open(client, 'inbox');
+    await open(client, 'work');
+    expect(ids()).toEqual(['w']);
+
+    const loading = open(client, 'inbox');
+    expect(ids()).toEqual(['a', 'b']);
+    expect(useEmailStore.getState().isLoading).toBe(false);
+
+    fresh.resolve({ emails: [makeEmail('new'), makeEmail('a'), makeEmail('b')], hasMore: false, total: 3, state: 's2' });
+    await loading;
+    expect(ids()).toEqual(['new', 'a', 'b']);
+    expect(useEmailStore.getState().emailListSync?.state).toBe('s2');
+  });
+
+  it('keeps the remembered rows when the refresh fails', async () => {
+    let inboxCalls = 0;
+    const { client } = makeClient({
+      inbox: async () => {
+        if (++inboxCalls > 1) throw new Error('rate limited; retry later');
+        return { emails: [makeEmail('a')], hasMore: false, total: 1, state: 's1' };
+      },
+      work: async () => ({ emails: [makeEmail('w')], hasMore: false, total: 1, state: 's1' }),
+    });
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+
+    await open(client, 'inbox');
+    await open(client, 'work');
+    await open(client, 'inbox');
+
+    expect(ids()).toEqual(['a']);
+    expect(useEmailStore.getState().error).toBe('rate limited; retry later');
+  });
+
+  it('remembers what happened to the list on screen, not the list as it was loaded', async () => {
+    const { client } = makeClient({
+      inbox: async () => ({ emails: [makeEmail('a'), makeEmail('b')], hasMore: false, total: 2, state: 's1' }),
+      work: async () => ({ emails: [makeEmail('w')], hasMore: false, total: 1, state: 's1' }),
+    });
+
+    await open(client, 'inbox');
+    useEmailStore.setState({ emails: [makeEmail('a', { keywords: { $seen: true } })], totalEmails: 1 });
+    await open(client, 'work');
+
+    useEmailStore.getState().selectMailbox('inbox');
+    void useEmailStore.getState().fetchEmails(client, 'inbox');
+    expect(ids()).toEqual(['a']);
+    expect(useEmailStore.getState().emails[0].keywords).toEqual({ $seen: true });
+  });
+
+  it('shows the spinner for a folder never opened in this tab', async () => {
+    const fresh = deferred<Page>();
+    const { client } = makeClient({
+      inbox: async () => ({ emails: [makeEmail('a')], hasMore: false, total: 1, state: 's1' }),
+      work: () => fresh.promise,
+    });
+
+    await open(client, 'inbox');
+    const loading = open(client, 'work');
+    expect(useEmailStore.getState().isLoading).toBe(true);
+    // The inbox rows stay up during the transition but are not this folder's.
+    fresh.resolve({ emails: [makeEmail('w')], hasMore: false, total: 1, state: 's1' });
+    await loading;
+    expect(ids()).toEqual(['w']);
+  });
+});
diff --git a/stores/email-store.ts b/stores/email-store.ts
index 38e881cad..acae4e44a 100644
--- a/stores/email-store.ts
+++ b/stores/email-store.ts
@@ -15,6 +15,7 @@ import { defaultSearchScopeFor, isAllFoldersSearchScope, SEARCH_SCOPE_ALL_FOLDER
 import { useAuthStore } from "@/stores/auth-store";
 import { pathNamesMailFolder } from "@/lib/deep-links";
 import { currentStoreEpoch } from "@/lib/store-epoch";
+import { folderListKey, forgetFolderLists, rememberFolderList, rememberedFolderList } from "@/lib/folder-list-cache";
 import { keywordPointer } from "@/lib/jmap/patch-pointer";
 import { useAccountStore } from "@/stores/account-store";
 import { useMessageListTabsStore } from "@/stores/message-list-tabs-store";
@@ -826,6 +827,13 @@ export function resolveEmailBlobContext(
 
 // List requests can finish after navigation. Never apply an old folder/tag
 // response (or error) to the view the user has since selected.
+/**
+ * The plain folder list on screen and the key it is remembered under (see
+ * lib/folder-list-cache). Null while the rows showing belong to no folder
+ * list - a search, a tag, a unified view, or a folder still loading.
+ */
+let shownFolderList: { key: string; mailboxId: string; pageSize: number } | null = null;
+
 function captureEmailListView(): () => boolean {
   const view = useEmailStore.getState();
   const activeAccountId = useAuthStore.getState().activeAccountId;
@@ -2037,7 +2045,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     // A background refresh (e.g. after an account switch restored a cached list)
     // repopulates the list without showing the loading overlay, so switching to
     // an already-visited account doesn't flash a spinner over the visible mail.
-    const background = opts?.background ?? false;
+    let background = opts?.background ?? false;
     // Loading a real mailbox is a fresh navigation (leaving any cross view), so
     // drop the unread/starred retain set and the held row.
     set(background ? { error: null, retainedInViewIds: new Set(), listHold: null } : { isLoading: true, error: null, retainedInViewIds: new Set(), listHold: null }); // Keep previous emails visible during transition
@@ -2154,6 +2162,38 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       // The configured list order (#718).
       const order = getMessageListOrderFor(mailbox?.role);
 
+      // Paint what this folder showed last time and load behind it: the rows
+      // are there at once, the fresh page replaces them when it lands, and a
+      // failed load leaves them in place instead of emptying the folder.
+      const listKey = folderListKey({
+        login: useAuthStore.getState().activeAccountId,
+        viewingAccountId: get().viewingAccountId,
+        // The login tells own accounts apart; a shared folder adds its owner.
+        accountId: accountId ?? '',
+        mailboxId: targetMailboxId,
+        filter: categoryFilter,
+        order,
+      });
+      const remembered = background ? undefined : rememberedFolderList(listKey);
+      if (remembered) {
+        background = true;
+        set({
+          emails: annotateScheduledEmails(remembered.emails, get().scheduledSubmissionByEmailId),
+          hasMoreEmails: remembered.hasMoreEmails,
+          totalEmails: remembered.totalEmails,
+          listOrder: order,
+          // The remembered page has no state a push delta could start from.
+          emailListSync: null,
+          threadEmailsCache: new Map(),
+          expandedThreadIds: new Set(),
+          isLoadingThread: null,
+          isLoading: false,
+        });
+      }
+      // Until this folder's rows are on screen, edits to the list belong to
+      // whatever was showing before and must not be remembered under this key.
+      shownFolderList = remembered ? { key: listKey, mailboxId: targetMailboxId, pageSize: emailsPerPage } : null;
+
       const result = await effectiveClient.getEmails(
         jmapMailboxId,
         accountId,
@@ -2189,6 +2229,8 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         isLoadingThread: null,
         isLoading: false
       });
+      shownFolderList = { key: listKey, mailboxId: targetMailboxId, pageSize: emailsPerPage };
+      rememberFolderList(listKey, get(), emailsPerPage);
       // Fetch full thread counts in the background (non-blocking)
       void get().fetchThreadEmailCounts(client);
     } catch (error) {
@@ -5980,6 +6022,30 @@ useEmailStore.subscribe((state, prev) => {
   state.holdListRow(listRowKey(email, state.isScheduledView));
 });
 
+// A folder's remembered list follows what happens to it on screen - a message
+// read, archived or deleted here is shown that way when the folder is opened
+// again, rather than as it was when the folder was loaded.
+useEmailStore.subscribe((state, prev) => {
+  if (state.mailboxes.length === 0 && state.emails.length === 0) {
+    shownFolderList = null;
+    forgetFolderLists();
+    return;
+  }
+  if (state.emails === prev.emails || !shownFolderList) return;
+  if (
+    state.selectedMailbox !== shownFolderList.mailboxId ||
+    state.searchQuery ||
+    !isFilterEmpty(state.searchFilters) ||
+    state.selectedKeyword ||
+    state.isUnifiedView ||
+    state.isScheduledView
+  ) {
+    shownFolderList = null;
+    return;
+  }
+  rememberFolderList(shownFolderList.key, state, shownFolderList.pageSize);
+});
+
 // ---------------------------------------------------------------------------
 // Boot snapshot: persist the mailbox list and the first page of the current
 // list so a returning visit paints rows the moment auth resolves, instead of

From 8abb817111a4ea11e29b66d9b90c79539e7e213b Mon Sep 17 00:00:00 2001
From: dealerweb <dealerweb@users.noreply.github.com>
Date: Thu, 8 Oct 2026 18:10:47 +0200
Subject: [PATCH 09/23] fix: keep a subject with runs of whitespace from
 freezing the tab title

The browser reads document.title back with its whitespace stripped and
collapsed, so a title with two spaces in a row, a tab or a space at the
edge never reads back as written. useDocumentTitle put its title back on
every <head> mutation whenever the two differed, and its own write was
such a mutation: an endless loop that froze the tab at full CPU, for
example on opening a message whose subject has two spaces in a row. It
now also accepts what the browser read back after its own write.
---
 hooks/__tests__/use-document-title.test.tsx | 29 +++++++++++++++++++++
 hooks/use-document-title.ts                 | 15 ++++++++---
 2 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/hooks/__tests__/use-document-title.test.tsx b/hooks/__tests__/use-document-title.test.tsx
index 7d359ab61..d6465aaea 100644
--- a/hooks/__tests__/use-document-title.test.tsx
+++ b/hooks/__tests__/use-document-title.test.tsx
@@ -71,6 +71,35 @@ describe('useDocumentTitle', () => {
     expect(document.title).toBe('Settings - Acme Mail');
   });
 
+  it('writes a title with runs of whitespace once instead of over and over', async () => {
+    // The browser reads the title back with its whitespace collapsed, so it
+    // never equals what was written. Count the writes, and stop a runaway
+    // loop instead of hanging the test.
+    const native = Object.getOwnPropertyDescriptor(Document.prototype, 'title')!;
+    let writes = 0;
+    Object.defineProperty(document, 'title', {
+      configurable: true,
+      get: () => native.get!.call(document),
+      set: (value: string) => {
+        writes += 1;
+        if (writes > 20) throw new Error('the title is written over and over');
+        native.set!.call(document, value);
+      },
+    });
+    try {
+      renderHook(() => useDocumentTitle('[Spam]  Offer\tinside '));
+      expect(document.title).toBe('[Spam] Offer inside - jane@example.com - Acme Mail');
+      expect(writes).toBe(1);
+      // Next renders its metadata title again: the title is put back once.
+      rerenderMetadataTitle();
+      await settle();
+      expect(document.title).toBe('[Spam] Offer inside - jane@example.com - Acme Mail');
+      expect(writes).toBe(2);
+    } finally {
+      delete (document as { title?: string }).title;
+    }
+  });
+
   it('puts its title back when the metadata title is rendered again', async () => {
     renderHook(() => useDocumentTitle('Settings'));
     rerenderMetadataTitle();
diff --git a/hooks/use-document-title.ts b/hooks/use-document-title.ts
index dc361bfe6..f91593177 100644
--- a/hooks/use-document-title.ts
+++ b/hooks/use-document-title.ts
@@ -36,10 +36,19 @@ export function useDocumentTitle(context?: string | null): void {
     if (!inView) return;
     const self = Symbol('document-title');
     owner = self;
-    // Termination: setting the title is itself a <head> mutation; on that run
-    // the title is already ours and nothing is written.
+    // Setting the title is itself a <head> mutation. The browser reads it
+    // back with its whitespace stripped and collapsed (HTML's "strip and
+    // collapse ASCII whitespace"), so a subject with two spaces in a row
+    // never reads back as written. Comparing with what it read back after
+    // our own write ends the round; without that, every write set off the
+    // observer again, an endless loop that froze the tab.
+    let readBack: string | null = null;
     const apply = () => {
-      if (owner === self && document.title !== title) document.title = title;
+      if (owner !== self) return;
+      const current = document.title;
+      if (current === title || current === readBack) return;
+      document.title = title;
+      readBack = document.title;
     };
     apply();
     const observer = new MutationObserver(apply);

From 19e06d02adcd2580586fea20fd11b498e69046c3 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Fri, 9 Oct 2026 08:27:01 +0200
Subject: [PATCH 10/23] fix(mountain-view): keep the same top bar on every app

Calendar, contacts, files and settings still drew the left navigation
rail under Mountain View, so moving away from mail switched to the
default frame. They now show the Mountain View top bar too, without the
mail search and the menu button, which only make sense in mail.
---
 components/calendar/calendar-app.tsx |  15 ++-
 components/contacts/contacts-app.tsx |  15 ++-
 components/files/files-app.tsx       |  15 ++-
 components/layout/mv-top-bar.tsx     | 167 ++++++++++++++-------------
 components/mail/mail-app.tsx         |  22 ++--
 components/settings/settings-app.tsx |  15 ++-
 hooks/use-mountain-view-shell.ts     |  19 +++
 7 files changed, 176 insertions(+), 92 deletions(-)
 create mode 100644 hooks/use-mountain-view-shell.ts

diff --git a/components/calendar/calendar-app.tsx b/components/calendar/calendar-app.tsx
index cfbce5667..b19cfff9c 100644
--- a/components/calendar/calendar-app.tsx
+++ b/components/calendar/calendar-app.tsx
@@ -92,6 +92,8 @@ import {
 import { useLiteLinkSegments } from "@/hooks/use-lite-link-segments";
 import { findMeetingLink } from "@/lib/event-links";
 import { useDocumentTitle } from "@/hooks/use-document-title";
+import { MvTopBar } from "@/components/layout/mv-top-bar";
+import { useMountainViewShell } from "@/hooks/use-mountain-view-shell";
 
 type PendingScopeAction =
   | { type: "edit"; event: CalendarEvent; updates: Partial<CalendarEvent>; sendScheduling?: boolean }
@@ -119,6 +121,8 @@ export function CalendarApp({ linkSegments: routeSegments }: CalendarAppProps =
   const isMobile = useIsMobile();
   const isDesktop = useIsDesktop();
   const isEmbedded = useIsEmbedded();
+  // Mountain View's desktop chrome: its top bar in place of the left rail.
+  const mvShell = useMountainViewShell(isEmbedded);
   // When the pane (Pro shell) or window is narrower than `lg`, the sidebar
   // collapses into a burger-toggled overlay instead of taking inline space.
   const isNarrow = !isDesktop;
@@ -1571,9 +1575,18 @@ export function CalendarApp({ linkSegments: routeSegments }: CalendarAppProps =
     <div className={cn("flex flex-col bg-background overflow-hidden pt-[env(safe-area-inset-top)]", isEmbedded ? "h-full" : "h-dvh")}>
       <AppTopBannerSlot />
       {refreshIndicator}
+      {mvShell && (
+        <MvTopBar
+          showMenuButton={false}
+          onManageApps={handleManageApps}
+          onInlineApp={handleInlineApp}
+          onCloseInlineApp={closeInlineApp}
+          activeAppId={inlineApp?.id ?? null}
+        />
+      )}
       <div className={cn("relative flex flex-1 min-h-0 overflow-hidden", isMobile && "flex-col")}>
       {/* Left Navigation Rail (hidden when embedded in Pro shell) */}
-      {!isMobile && !isEmbedded && (
+      {!isMobile && !isEmbedded && !mvShell && (
         <div className="w-14 bg-secondary flex flex-col flex-shrink-0" style={{ borderRight: '1px solid rgba(128, 128, 128, 0.3)' }}>
           <NavigationRail
             collapsed
diff --git a/components/contacts/contacts-app.tsx b/components/contacts/contacts-app.tsx
index 011a4afd0..944c6b496 100644
--- a/components/contacts/contacts-app.tsx
+++ b/components/contacts/contacts-app.tsx
@@ -44,6 +44,8 @@ import { useDeepLinkUrl } from "@/hooks/use-deep-link-url";
 import { useProInterfaceActive } from "@/components/pro/pro-interface-redirect";
 import { useLiteLinkSegments } from "@/hooks/use-lite-link-segments";
 import { useDocumentTitle } from "@/hooks/use-document-title";
+import { MvTopBar } from "@/components/layout/mv-top-bar";
+import { useMountainViewShell } from "@/hooks/use-mountain-view-shell";
 
 type View =
   | "list"
@@ -125,6 +127,8 @@ function ContactsAppContent({ linkSegments: routeSegments }: ContactsAppProps =
   const isMobile = useIsMobile();
   const isDesktop = useIsDesktop();
   const isEmbedded = useIsEmbedded();
+  // Mountain View's desktop chrome: its top bar in place of the left rail.
+  const mvShell = useMountainViewShell(isEmbedded);
   const router = useRouter();
   const searchParams = useSearchParams();
   // One-shot intent flag: only consume the URL params on the first render that
@@ -899,9 +903,18 @@ function ContactsAppContent({ linkSegments: routeSegments }: ContactsAppProps =
     <div className={cn("flex flex-col bg-background overflow-hidden pt-[env(safe-area-inset-top)]", isEmbedded ? "h-full" : "h-dvh")}>
       <AppTopBannerSlot />
       {refreshIndicator}
+      {mvShell && (
+        <MvTopBar
+          showMenuButton={false}
+          onManageApps={handleManageApps}
+          onInlineApp={handleInlineApp}
+          onCloseInlineApp={closeInlineApp}
+          activeAppId={inlineApp?.id ?? null}
+        />
+      )}
       <div className={cn("flex flex-1 min-h-0 overflow-hidden", isMobile && "flex-col")}>
       {/* Navigation Rail - desktop only (hidden when embedded in Pro shell) */}
-      {!isMobile && !isEmbedded && (
+      {!isMobile && !isEmbedded && !mvShell && (
         <div className="w-14 bg-secondary flex flex-col flex-shrink-0" style={{ borderRight: '1px solid rgba(128, 128, 128, 0.3)' }}>
           <NavigationRail
             collapsed
diff --git a/components/files/files-app.tsx b/components/files/files-app.tsx
index 3ea94c2eb..a2235b960 100644
--- a/components/files/files-app.tsx
+++ b/components/files/files-app.tsx
@@ -39,6 +39,8 @@ import { useDeepLinkUrl } from "@/hooks/use-deep-link-url";
 import { useProInterfaceActive } from "@/components/pro/pro-interface-redirect";
 import { useLiteLinkSegments } from "@/hooks/use-lite-link-segments";
 import { useDocumentTitle } from "@/hooks/use-document-title";
+import { MvTopBar } from "@/components/layout/mv-top-bar";
+import { useMountainViewShell } from "@/hooks/use-mountain-view-shell";
 
 export interface FilesAppProps {
   /** Path segments after `/files` - the folder path, one segment per level. */
@@ -114,6 +116,8 @@ export function FilesApp({ linkSegments: routeSegments }: FilesAppProps = {}) {
 
   const isMobile = useIsMobile();
   const isEmbedded = useIsEmbedded();
+  // Mountain View's desktop chrome: its top bar in place of the left rail.
+  const mvShell = useMountainViewShell(isEmbedded);
   const [folderLayout, setFolderLayout] = useState<FolderLayout>(() => loadFilesSettings().folderLayout);
   // The account the files client was last initialised for (`undefined` = never).
   // Tracked so a Pro-shell account switch re-initialises instead of showing the
@@ -573,8 +577,17 @@ export function FilesApp({ linkSegments: routeSegments }: FilesAppProps = {}) {
     <div className={cn("flex flex-col bg-background overflow-hidden pt-[env(safe-area-inset-top)]", isEmbedded ? "h-full" : "h-dvh")}>
       <AppTopBannerSlot />
       {refreshIndicator}
+      {mvShell && (
+        <MvTopBar
+          showMenuButton={false}
+          onManageApps={handleManageApps}
+          onInlineApp={handleInlineApp}
+          onCloseInlineApp={closeInlineApp}
+          activeAppId={inlineApp?.id ?? null}
+        />
+      )}
       <div className="flex flex-1 min-h-0 overflow-hidden">
-      {!isMobile && !isEmbedded && (
+      {!isMobile && !isEmbedded && !mvShell && (
         <div className="w-14 bg-secondary flex flex-col flex-shrink-0" style={{ borderRight: '1px solid rgba(128, 128, 128, 0.3)' }}>
           <NavigationRail
             collapsed
diff --git a/components/layout/mv-top-bar.tsx b/components/layout/mv-top-bar.tsx
index ae1a3a0a3..007e7d9c8 100644
--- a/components/layout/mv-top-bar.tsx
+++ b/components/layout/mv-top-bar.tsx
@@ -30,25 +30,18 @@ import { AccountSwitcher } from "@/components/layout/account-switcher";
 import { SearchBox, type ContactSearchField } from "@/components/search/search-box";
 import type { ContactSuggestion } from "@/lib/search-suggestions";
 
-interface MvTopBarProps {
-  searchQuery: string;
-  onSearchQueryChange: (value: string) => void;
-  onSearchSubmit: (query: string) => void;
-  onSearchClear: () => void;
+/** Mail search, which only the mail surface puts into the bar. */
+interface MvTopBarSearch {
+  query: string;
+  onQueryChange: (value: string) => void;
+  onSubmit: (query: string) => void;
+  onClear: () => void;
   onSelectContact: (contact: ContactSuggestion, field: ContactSearchField) => void;
   /** Opens the advanced-filter panel that lives under the message list. */
   onToggleFilters: () => void;
   filtersOpen: boolean;
   activeFilterCount: number;
-  searchDisabled?: boolean;
-  onShowShortcuts?: () => void;
-  onManageApps?: () => void;
-  onInlineApp?: (appId: string, url: string, name: string) => void;
-  onCloseInlineApp?: () => void;
-  activeAppId?: string | null;
-  /** Opens the merged across-accounts inbox from the account popover. */
-  onSelectAllInboxes?: () => void;
-  allInboxesSelected?: boolean;
+  disabled?: boolean;
   /**
    * Receives the node under the search field that the advanced-filter panel is
    * portalled into, so the panel drops from the field itself; without this
@@ -58,23 +51,36 @@ interface MvTopBarProps {
   onFilterAnchorChange?: (node: HTMLDivElement | null) => void;
 }
 
+interface MvTopBarProps {
+  /**
+   * The mail search field. Other surfaces leave it out and keep their own
+   * search where it was; the bar then carries the brand, the app grid and the
+   * account avatar only.
+   */
+  search?: MvTopBarSearch;
+  /** The hamburger folds the mail navigation, so only mail shows it. */
+  showMenuButton?: boolean;
+  onShowShortcuts?: () => void;
+  onManageApps?: () => void;
+  onInlineApp?: (appId: string, url: string, name: string) => void;
+  onCloseInlineApp?: () => void;
+  activeAppId?: string | null;
+  /** Opens the merged across-accounts inbox from the account popover. */
+  onSelectAllInboxes?: () => void;
+  allInboxesSelected?: boolean;
+}
+
 /**
  * Mountain View's global header: one 64px row that owns the hamburger, the
  * brand, the search field and the account cluster. It only renders on
- * desktop under `interfaceLayout === 'mountain-view'`; the default layout keeps
- * search inside the list column and navigation in the left rail, and neither
- * of those is touched here.
+ * desktop under `interfaceLayout === 'mountain-view'` (see
+ * useMountainViewShell), on every surface, in place of the left rail; the
+ * default layout keeps search inside the list column and navigation in the
+ * left rail, and neither of those is touched here.
  */
 export function MvTopBar({
-  searchQuery,
-  onSearchQueryChange,
-  onSearchSubmit,
-  onSearchClear,
-  onSelectContact,
-  onToggleFilters,
-  filtersOpen,
-  activeFilterCount,
-  searchDisabled = false,
+  search,
+  showMenuButton = true,
   onShowShortcuts,
   onManageApps,
   onInlineApp,
@@ -82,7 +88,6 @@ export function MvTopBar({
   activeAppId,
   onSelectAllInboxes,
   allInboxesSelected = false,
-  onFilterAnchorChange,
 }: MvTopBarProps) {
   const t = useTranslations("sidebar");
   const tSearch = useTranslations("advanced_search");
@@ -96,6 +101,8 @@ export function MvTopBar({
   const calendarEnabled = usePolicyStore((s) => s.isFeatureEnabled("calendarEnabled"));
   const contactsEnabled = usePolicyStore((s) => s.isFeatureEnabled("contactsEnabled"));
   const filesEnabled = usePolicyStore((s) => s.isFeatureEnabled("filesEnabled"));
+  // The same gate the navigation rail puts on its "add app" button.
+  const sidebarAppsEnabled = usePolicyStore((s) => s.isFeatureEnabled("sidebarAppsEnabled"));
   const sidebarApps = useResolvedSidebarApps();
 
   const [appsOpen, setAppsOpen] = useState(false);
@@ -147,15 +154,17 @@ export function MvTopBar({
       data-mv-topbar=""
     >
       {/* Brand block: occupies the sidebar's own column width */}
-      <div className="flex items-center gap-1 shrink-0">
-        <button
-          type="button"
-          onClick={toggleSidebarCollapsed}
-          className="grid place-items-center w-12 h-12 rounded-full text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
-          aria-label={t("mobile.toggle_menu")}
-        >
-          <Menu className="w-5 h-5" />
-        </button>
+      <div className={cn("flex items-center gap-1 shrink-0", !showMenuButton && "ps-3")}>
+        {showMenuButton && (
+          <button
+            type="button"
+            onClick={toggleSidebarCollapsed}
+            className="grid place-items-center w-12 h-12 rounded-full text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
+            aria-label={t("mobile.toggle_menu")}
+          >
+            <Menu className="w-5 h-5" />
+          </button>
+        )}
         <Link href="/" className="flex items-center gap-2 pe-4 min-w-0" aria-label={appName}>
           {logoUrl ? <img src={logoUrl} alt="" className="w-8 h-8 object-contain" /> : null}
           <span className="text-[22px] leading-none text-foreground/80 truncate">{appName}</span>
@@ -163,48 +172,50 @@ export function MvTopBar({
       </div>
 
       {/* Search: left-anchored and capped, not centred */}
-      <div className="mv-topbar-search relative flex items-center gap-1 flex-1 min-w-0 max-w-[720px]">
-        <SearchBox
-          value={searchQuery}
-          onChange={onSearchQueryChange}
-          onSubmit={onSearchSubmit}
-          onClear={onSearchClear}
-          onSelectContact={onSelectContact}
-          disabled={searchDisabled}
-        />
-        <button
-          type="button"
-          onClick={onToggleFilters}
-          disabled={searchDisabled}
-          // Inside the field's trailing end, next to the typed query.
-          className={cn(
-            "absolute end-1 top-1/2 -translate-y-1/2 z-10 grid place-items-center w-10 h-10 rounded-full transition-colors",
-            searchDisabled && "opacity-50 cursor-not-allowed",
-            filtersOpen || activeFilterCount > 0
-              ? "bg-primary/10 text-primary"
-              : "text-muted-foreground hover:bg-muted hover:text-foreground"
-          )}
-          title={tSearch("toggle_filters")}
-          aria-label={tSearch("toggle_filters")}
-        >
-          <Filter className="w-5 h-5" />
-          {!filtersOpen && activeFilterCount > 0 && (
-            <span className="absolute top-1.5 end-1.5 grid place-items-center w-4 h-4 text-[10px] font-bold rounded-full bg-primary text-primary-foreground">
-              {activeFilterCount}
-            </span>
-          )}
-        </button>
+      {search && (
+        <div className="mv-topbar-search relative flex items-center gap-1 flex-1 min-w-0 max-w-[720px]">
+          <SearchBox
+            value={search.query}
+            onChange={search.onQueryChange}
+            onSubmit={search.onSubmit}
+            onClear={search.onClear}
+            onSelectContact={search.onSelectContact}
+            disabled={search.disabled}
+          />
+          <button
+            type="button"
+            onClick={search.onToggleFilters}
+            disabled={search.disabled}
+            // Inside the field's trailing end, next to the typed query.
+            className={cn(
+              "absolute end-1 top-1/2 -translate-y-1/2 z-10 grid place-items-center w-10 h-10 rounded-full transition-colors",
+              search.disabled && "opacity-50 cursor-not-allowed",
+              search.filtersOpen || search.activeFilterCount > 0
+                ? "bg-primary/10 text-primary"
+                : "text-muted-foreground hover:bg-muted hover:text-foreground"
+            )}
+            title={tSearch("toggle_filters")}
+            aria-label={tSearch("toggle_filters")}
+          >
+            <Filter className="w-5 h-5" />
+            {!search.filtersOpen && search.activeFilterCount > 0 && (
+              <span className="absolute top-1.5 end-1.5 grid place-items-center w-4 h-4 text-[10px] font-bold rounded-full bg-primary text-primary-foreground">
+                {search.activeFilterCount}
+              </span>
+            )}
+          </button>
 
-        {/* Anchor for the advanced-filter panel: the search field's own box,
-            filter button included, so the panel shares the field's edges. It
-            only marks the spot; the panel itself is drawn at the end of <body>. */}
-        <div
-          ref={onFilterAnchorChange}
-          aria-hidden
-          data-mv-filter-anchor=""
-          className="pointer-events-none absolute start-0 end-0 top-full h-0"
-        />
-      </div>
+          {/* Anchor for the advanced-filter panel: the search field's own box,
+              filter button included, so the panel shares the field's edges. It
+              only marks the spot; the panel itself is drawn at the end of <body>. */}
+          <div
+            ref={search.onFilterAnchorChange}
+            aria-hidden
+            data-mv-filter-anchor=""
+            className="pointer-events-none absolute start-0 end-0 top-full h-0"
+          />
+        </div>
+      )}
 
       {/* Spacer keeps the right cluster pinned while search stays left */}
       <div className="flex-1 min-w-0" />
@@ -306,7 +317,7 @@ export function MvTopBar({
                   );
                 })}
               </div>
-              {onManageApps && (
+              {sidebarAppsEnabled && onManageApps && (
                 <button
                   type="button"
                   role="menuitem"
diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index 4e8207626..2ab93c9e0 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -3857,15 +3857,18 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
         )}
         {mvShell && !fullscreenReading && (
           <MvTopBar
-            searchQuery={searchQuery}
-            onSearchQueryChange={setSearchQuery}
-            onSearchSubmit={handleSearch}
-            onSearchClear={handleClearSearch}
-            onSelectContact={handleSelectContactSuggestion}
-            onToggleFilters={toggleAdvancedSearch}
-            filtersOpen={isAdvancedSearchOpen}
-            activeFilterCount={activeFilterCount(searchFilters)}
-            searchDisabled={isScheduledView}
+            search={{
+              query: searchQuery,
+              onQueryChange: setSearchQuery,
+              onSubmit: handleSearch,
+              onClear: handleClearSearch,
+              onSelectContact: handleSelectContactSuggestion,
+              onToggleFilters: toggleAdvancedSearch,
+              filtersOpen: isAdvancedSearchOpen,
+              activeFilterCount: activeFilterCount(searchFilters),
+              disabled: isScheduledView,
+              onFilterAnchorChange: setFilterAnchor,
+            }}
             onShowShortcuts={() => setShowShortcutsModal(true)}
             onManageApps={handleManageApps}
             onInlineApp={handleInlineApp}
@@ -3875,7 +3878,6 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
               allInboxesReachable ? () => handleMailboxSelect(UNIFIED_MAILBOX_IDS.inbox) : undefined
             }
             allInboxesSelected={allInboxesSelected}
-            onFilterAnchorChange={setFilterAnchor}
           />
         )}
         <div className="flex flex-1 overflow-hidden">
diff --git a/components/settings/settings-app.tsx b/components/settings/settings-app.tsx
index ed29a460c..5bed3f0ff 100644
--- a/components/settings/settings-app.tsx
+++ b/components/settings/settings-app.tsx
@@ -103,6 +103,8 @@ import {
 } from '@/lib/settings-search';
 import { useLiteLinkSegments } from '@/hooks/use-lite-link-segments';
 import { useDocumentTitle } from '@/hooks/use-document-title';
+import { MvTopBar } from "@/components/layout/mv-top-bar";
+import { useMountainViewShell } from "@/hooks/use-mountain-view-shell";
 
 type Tab = SettingsSearchTab;
 
@@ -222,6 +224,8 @@ export function SettingsApp({ linkSegments: routeSegments }: SettingsAppProps =
   const { client, isAuthenticated, logout, checkAuth, isLoading: authLoading } = useAuthStore();
   const { showAppsModal, inlineApp, loadedApps, handleManageApps, handleInlineApp, closeInlineApp, closeAppsModal } = useSidebarApps();
   const isEmbedded = useIsEmbedded();
+  // Mountain View's desktop chrome: its top bar in place of the left rail.
+  const mvShell = useMountainViewShell(isEmbedded);
   const [initialCheckDone, setInitialCheckDone] = useState(() => useAuthStore.getState().isAuthenticated && !!useAuthStore.getState().client);
   const { quota, isPushConnected } = useEmailStore();
   const { stalwartFeaturesEnabled } = useConfig();
@@ -867,8 +871,17 @@ export function SettingsApp({ linkSegments: routeSegments }: SettingsAppProps =
   return (
     <div className={cn("flex flex-col bg-background pt-[env(safe-area-inset-top)]", isEmbedded ? "h-full" : "h-dvh")}>
       <AppTopBannerSlot />
+      {mvShell && (
+        <MvTopBar
+          showMenuButton={false}
+          onManageApps={handleManageApps}
+          onInlineApp={handleInlineApp}
+          onCloseInlineApp={closeInlineApp}
+          activeAppId={inlineApp?.id ?? null}
+        />
+      )}
       <div className="flex flex-1 min-h-0">
-      {!isEmbedded && (
+      {!isEmbedded && !mvShell && (
         <div className="w-14 bg-secondary flex flex-col flex-shrink-0" style={{ borderRight: '1px solid rgba(128, 128, 128, 0.3)' }}>
           <NavigationRail
             collapsed
diff --git a/hooks/use-mountain-view-shell.ts b/hooks/use-mountain-view-shell.ts
new file mode 100644
index 000000000..872ca177f
--- /dev/null
+++ b/hooks/use-mountain-view-shell.ts
@@ -0,0 +1,19 @@
+"use client";
+
+import { useIsDesktop } from "@/hooks/use-media-query";
+import { useSettingsStore } from "@/stores/settings-store";
+
+/**
+ * Whether a surface draws Mountain View's desktop chrome: the top bar with the
+ * app grid and the account avatar, in place of the left navigation rail.
+ *
+ * Mail, calendar, contacts, files and settings all ask the same question, so
+ * moving between them under Mountain View keeps the same frame. Phones and
+ * tablets keep their own navigation, and so does a surface embedded in a Pro
+ * pane, whose shell owns the chrome.
+ */
+export function useMountainViewShell(isEmbedded: boolean): boolean {
+  const mountainView = useSettingsStore((s) => s.interfaceLayout === "mountain-view");
+  const isDesktop = useIsDesktop();
+  return mountainView && isDesktop && !isEmbedded;
+}

From 7c35ed360fd9861fd246537aac28900a7aafc2b2 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Fri, 9 Oct 2026 08:27:01 +0200
Subject: [PATCH 11/23] fix(mountain-view): labels, selection and controls that
 did not match

- The refresh button was labelled "Loading" and the overflow menu
  "Mark folder as read"; they now say Refresh and More actions.
- The Starred row stayed highlighted while a tag was open, and its icon
  ignored the colourful-icons setting.
- Reply, Reply all and Forward use the standard small button size.
- With a single login the account popover offers one Sign out pill
  instead of a pill-less footer row.
- The compose backdrop matches the other dialogs.
- Layout settings hide the mail layout and toolbar label options, which
  do nothing under Mountain View; their values still apply to the
  default layout.
---
 .../email/__tests__/mv-list-toolbar.test.tsx  |  2 +-
 components/email/email-viewer.tsx             |  6 ++--
 components/email/mv-compose-window.tsx        |  2 +-
 components/email/mv-list-toolbar.tsx          |  8 +++--
 components/layout/account-switcher.tsx        | 29 +++++++++----------
 components/layout/sidebar.tsx                 |  5 ++--
 components/settings/layout-settings.tsx       |  9 +++++-
 7 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/components/email/__tests__/mv-list-toolbar.test.tsx b/components/email/__tests__/mv-list-toolbar.test.tsx
index 0d9fd71ea..22a6006ef 100644
--- a/components/email/__tests__/mv-list-toolbar.test.tsx
+++ b/components/email/__tests__/mv-list-toolbar.test.tsx
@@ -120,7 +120,7 @@ describe('MvListToolbar overflow menu', () => {
     } as never);
   });
 
-  const open = () => fireEvent.click(screen.getAllByLabelText('mark_folder_read')[0]);
+  const open = () => fireEvent.click(screen.getByLabelText('more_actions'));
 
   it('offers marking every folder read, not just this one', () => {
     render(
diff --git a/components/email/email-viewer.tsx b/components/email/email-viewer.tsx
index 315c4c426..c23f22eba 100644
--- a/components/email/email-viewer.tsx
+++ b/components/email/email-viewer.tsx
@@ -5433,15 +5433,15 @@ export function EmailViewer({
               className={cn("pb-6 pt-2", isMobile ? "grid grid-cols-3 gap-2 px-4" : "flex flex-wrap items-center gap-2 px-6")}
               data-mv-reply-row=""
             >
-              <Button variant="outline" className={cn("h-9 rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={() => onReply?.()}>
+              <Button variant="outline" size="sm" className={cn("rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={() => onReply?.()}>
                 <Reply className="w-4 h-4" />
                 {t('reply')}
               </Button>
-              <Button variant="outline" className={cn("h-9 rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={onReplyAll}>
+              <Button variant="outline" size="sm" className={cn("rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={onReplyAll}>
                 <ReplyAll className="w-4 h-4" />
                 {t('reply_all')}
               </Button>
-              <Button variant="outline" className={cn("h-9 rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={onForward}>
+              <Button variant="outline" size="sm" className={cn("rounded-full gap-2", isMobile ? "min-w-0 px-2 text-xs" : "px-5")} onClick={onForward}>
                 <Forward className="w-4 h-4" />
                 {t('forward')}
               </Button>
diff --git a/components/email/mv-compose-window.tsx b/components/email/mv-compose-window.tsx
index 6febf5937..45a17f1d9 100644
--- a/components/email/mv-compose-window.tsx
+++ b/components/email/mv-compose-window.tsx
@@ -23,7 +23,7 @@ export function MvComposeWindow({ children }: { children: ReactNode }) {
     <>
       {maximized && (
         <div
-          className="fixed inset-0 z-40 bg-black/40"
+          className="fixed inset-0 z-40 bg-black/50"
           aria-hidden
           onClick={() => setState("normal")}
         />
diff --git a/components/email/mv-list-toolbar.tsx b/components/email/mv-list-toolbar.tsx
index 3f320d975..1631c972d 100644
--- a/components/email/mv-list-toolbar.tsx
+++ b/components/email/mv-list-toolbar.tsx
@@ -100,6 +100,8 @@ export function MvListToolbar({
   const tFolder = useTranslations("mailbox_context_menu");
   const tMenu = useTranslations("context_menu");
   const tSidebar = useTranslations("sidebar");
+  const tCommon = useTranslations("common");
+  const tViewer = useTranslations("email_viewer");
 
   const client = useAuthStore((s) => s.client);
   const {
@@ -328,7 +330,7 @@ export function MvListToolbar({
 
       <ToolbarButton
         icon={RotateCcw}
-        label={t("loading")}
+        label={tCommon("refresh")}
         onClick={onRefresh}
         disabled={!client || isRefreshing}
         busy={isRefreshing}
@@ -341,8 +343,8 @@ export function MvListToolbar({
           onClick={() => setMenuOpen((v) => !v)}
           aria-haspopup="menu"
           aria-expanded={menuOpen}
-          title={tFolder("mark_folder_read")}
-          aria-label={tFolder("mark_folder_read")}
+          title={tViewer("more_actions")}
+          aria-label={tViewer("more_actions")}
           className={cn(
             "grid place-items-center w-10 h-10 rounded-full transition-colors",
             menuOpen
diff --git a/components/layout/account-switcher.tsx b/components/layout/account-switcher.tsx
index 07f760119..6860f976b 100644
--- a/components/layout/account-switcher.tsx
+++ b/components/layout/account-switcher.tsx
@@ -451,7 +451,7 @@ export function AccountSwitcher({
           </div>
 
           {/* Mountain View: "Add another account" and "Sign out of all accounts" as two
-              pills side by side. */}
+              pills side by side; with a single login the second is plain "Sign out". */}
           {mvPopover && (
             <div className="flex flex-wrap items-center justify-center gap-2 border-t border-border px-4 py-3" data-mv-account-actions="">
               {accounts.length < getMaxAccounts() && (
@@ -465,16 +465,14 @@ export function AccountSwitcher({
                   {t("add_account")}
                 </button>
               )}
-              {accounts.length > 1 && (
-                <button
-                  onClick={handleLogoutAll}
-                  className="flex items-center gap-2 rounded-full border border-border px-4 py-2 text-sm hover:bg-muted transition-colors"
-                  role="menuitem"
-                >
-                  <LogOut className="w-4 h-4" />
-                  {t("sign_out_all")}
-                </button>
-              )}
+              <button
+                onClick={accounts.length > 1 ? handleLogoutAll : handleLogout}
+                className="flex items-center gap-2 rounded-full border border-border px-4 py-2 text-sm hover:bg-muted transition-colors"
+                role="menuitem"
+              >
+                <LogOut className="w-4 h-4" />
+                {accounts.length > 1 ? t("sign_out_all") : t("sign_out")}
+              </button>
             </div>
           )}
 
@@ -493,12 +491,13 @@ export function AccountSwitcher({
             </div>
           )}
 
-          {/* Separator + Actions */}
-          <div className="border-t border-border">
+          {/* Separator + Actions. Under Mountain View a single login signs out
+              from the pill above, so these rows are only for picking among several. */}
+          <div className={cn("border-t border-border", mvPopover && accounts.length < 2 && "hidden")}>
             {activeAccount && !activeAccount.isDefault && accounts.length > 1 && (
               <button
                 onClick={() => handleSetDefault(activeAccount.id)}
-                className="w-full flex items-center gap-2 px-3 py-2 text-sm text-foreground hover:bg-muted transition-colors"
+                className={cn("w-full flex items-center gap-2 py-2 text-sm text-foreground hover:bg-muted transition-colors", mvPopover ? "px-4" : "px-3")}
                 role="menuitem"
               >
                 <Star className="w-4 h-4" />
@@ -507,7 +506,7 @@ export function AccountSwitcher({
             )}
             <button
               onClick={handleLogout}
-              className="w-full flex items-center gap-2 px-3 py-2 text-sm text-foreground hover:bg-muted transition-colors"
+              className={cn("w-full flex items-center gap-2 py-2 text-sm text-foreground hover:bg-muted transition-colors", mvPopover ? "px-4" : "px-3")}
               role="menuitem"
             >
               <LogOut className="w-4 h-4" />
diff --git a/components/layout/sidebar.tsx b/components/layout/sidebar.tsx
index 7de0d1eb7..452cacfdc 100644
--- a/components/layout/sidebar.tsx
+++ b/components/layout/sidebar.tsx
@@ -1483,11 +1483,12 @@ export function Sidebar({
                         {/* Mountain View lists Starred right under the Inbox. */}
                         {mvFlat && node.role === 'inbox' && onOpenStarred && (
                           <SidebarRow
-                            icon={<Star className="w-4 h-4 text-muted-foreground" />}
+                            // Drawn like the "All starred" row it stands in for.
+                            icon={<Star className={getIconClass(!selectedKeyword && selectedMailbox === CROSS_VIEW_IDS.starred, false, colorfulSidebarIcons)} />}
                             label={t("mailboxes.starred")}
                             testName="mv-starred"
                             depth={0}
-                            isSelected={selectedMailbox === CROSS_VIEW_IDS.starred}
+                            isSelected={!selectedKeyword && selectedMailbox === CROSS_VIEW_IDS.starred}
                             onClick={onOpenStarred}
                             isCollapsed={false}
                           />
diff --git a/components/settings/layout-settings.tsx b/components/settings/layout-settings.tsx
index d304076ac..a3700157d 100644
--- a/components/settings/layout-settings.tsx
+++ b/components/settings/layout-settings.tsx
@@ -166,6 +166,8 @@ export function LayoutSettings() {
     ? t('all_mail.account_hint', { account: activeAccount.displayName || activeAccount.email })
     : null;
 
+  const mountainView = interfaceLayout === 'mountain-view';
+
   return (
     <SettingsSection title={t('title')} description={t('description')}>
       {/* The interface layout decides where search, navigation and toolbars
@@ -182,7 +184,10 @@ export function LayoutSettings() {
         />
       </SettingItem>
       )}
-      {!isSettingHidden('mailLayout') && (
+      {/* Mountain View always shows the list and then the conversation, and
+          its toolbars are icon-only, so these two would change nothing there.
+          Their saved values stay and apply again under the default layout. */}
+      {!isSettingHidden('mailLayout') && !mountainView && (
       <SettingItem label={tEmail('mail_layout.label')} description={tEmail('mail_layout.description')} locked={isSettingLocked('mailLayout')}>
         <div className="w-[22rem] max-w-full">
           <RadioGroup
@@ -210,12 +215,14 @@ export function LayoutSettings() {
         />
       </SettingItem>
 
+      {!mountainView && (
       <SettingItem label={t('toolbar_labels.label')} description={t('toolbar_labels.description')}>
         <ToggleSwitch
           checked={showToolbarLabels}
           onChange={(checked) => updateSetting('showToolbarLabels', checked)}
         />
       </SettingItem>
+      )}
 
       <SettingItem label={t('hide_account_switcher.label')} description={t('hide_account_switcher.description')}>
         <ToggleSwitch

From 4347d25890e0a614344ee5fb68ec25945cafac69 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Fri, 9 Oct 2026 08:28:40 +0200
Subject: [PATCH 12/23] fix(mountain-view): show the admin console link in the
 top bar

The top bar replaces the navigation rail on desktop, and with it went
the shield that takes a Stalwart admin to the console, so an admin under
Mountain View had no way in. The bar now shows it, with the same update
dot. The check that decides it moves out of the rail into
useStalwartAdmin so both use the same one.
---
 components/layout/mv-top-bar.tsx           | 30 ++++++++++++-
 components/layout/navigation-rail.tsx      | 31 ++-----------
 hooks/__tests__/use-stalwart-admin.test.ts | 51 ++++++++++++++++++++++
 hooks/use-stalwart-admin.ts                | 39 +++++++++++++++++
 4 files changed, 122 insertions(+), 29 deletions(-)
 create mode 100644 hooks/__tests__/use-stalwart-admin.test.ts
 create mode 100644 hooks/use-stalwart-admin.ts

diff --git a/components/layout/mv-top-bar.tsx b/components/layout/mv-top-bar.tsx
index 007e7d9c8..ec5cc51d5 100644
--- a/components/layout/mv-top-bar.tsx
+++ b/components/layout/mv-top-bar.tsx
@@ -11,6 +11,7 @@ import {
   Mail,
   Menu,
   Settings,
+  Shield,
   iconForName,
 } from "@/components/icons";
 import type { AppIcon as AppIconType } from "@/components/icons";
@@ -24,7 +25,9 @@ import { useResolvedSidebarApps } from "@/hooks/use-resolved-sidebar-apps";
 import { useThemeStore } from "@/stores/theme-store";
 import { useUIStore } from "@/stores/ui-store";
 import { useMenuNavigation } from "@/hooks/use-menu-navigation";
-import { withBasePath } from "@/lib/browser-navigation";
+import { getPathPrefix, withBasePath } from "@/lib/browser-navigation";
+import { useStalwartAdmin } from "@/hooks/use-stalwart-admin";
+import { useUpdateStore, selectHasUpdate } from "@/stores/update-store";
 import { cn } from "@/lib/utils";
 import { AccountSwitcher } from "@/components/layout/account-switcher";
 import { SearchBox, type ContactSearchField } from "@/components/search/search-box";
@@ -104,6 +107,10 @@ export function MvTopBar({
   // The same gate the navigation rail puts on its "add app" button.
   const sidebarAppsEnabled = usePolicyStore((s) => s.isFeatureEnabled("sidebarAppsEnabled"));
   const sidebarApps = useResolvedSidebarApps();
+  const isStalwartAdmin = useStalwartAdmin();
+  const hasUpdate = useUpdateStore(selectHasUpdate);
+  const updateSeverity = useUpdateStore((s) => s.status?.severity);
+  const updateImportant = updateSeverity === "security" || updateSeverity === "deprecated";
 
   const [appsOpen, setAppsOpen] = useState(false);
   const appsButtonRef = useRef<HTMLButtonElement>(null);
@@ -232,6 +239,27 @@ export function MvTopBar({
             <Keyboard className="w-5 h-5" />
           </button>
         )}
+        {/* Admin (Stalwart admins), as in the navigation rail this bar replaces.
+            A hard navigation because /admin lives outside the [locale] tree. */}
+        {isStalwartAdmin && (
+          <a
+            href={`${getPathPrefix()}/admin`}
+            className="relative grid place-items-center w-12 h-12 rounded-full text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
+            title={t("admin")}
+            aria-label={t("admin")}
+          >
+            <Shield className="w-5 h-5" />
+            {hasUpdate && (
+              <span
+                className={cn(
+                  "absolute top-3 end-3 w-2 h-2 rounded-full ring-2 ring-background",
+                  updateImportant ? "bg-red-500" : "bg-amber-500",
+                )}
+                aria-label={updateImportant ? "Important update available" : "Update available"}
+              />
+            )}
+          </a>
+        )}
         <Link
           href="/settings"
           className="grid place-items-center w-12 h-12 rounded-full text-muted-foreground hover:bg-muted hover:text-foreground transition-colors"
diff --git a/components/layout/navigation-rail.tsx b/components/layout/navigation-rail.tsx
index 66cabd71d..2021e30ed 100644
--- a/components/layout/navigation-rail.tsx
+++ b/components/layout/navigation-rail.tsx
@@ -17,16 +17,15 @@ import { useResolvedSidebarApps } from "@/hooks/use-resolved-sidebar-apps";
 import { useAuthStore } from "@/stores/auth-store";
 import { useAccountStore } from "@/stores/account-store";
 import { useUpdateStore, selectHasUpdate } from "@/stores/update-store";
-import { getActiveAccountSlotHeaders } from "@/lib/auth/active-account-slot";
 import { getMaxAccounts } from "@/lib/account-utils";
 import { isDocumentRTL } from "@/i18n/direction";
 import { cn, formatFileSize } from "@/lib/utils";
 import { useMenuNavigation } from "@/hooks/use-menu-navigation";
 import { PluginSlot } from "@/components/plugins/plugin-slot";
+import { useStalwartAdmin } from "@/hooks/use-stalwart-admin";
 import { KeyboardShortcutsModal } from "@/components/keyboard-shortcuts-modal";
-import { apiFetch, getPathPrefix, withBasePath } from "@/lib/browser-navigation";
+import { getPathPrefix, withBasePath } from "@/lib/browser-navigation";
 import { Avatar } from "@/components/ui/avatar";
-import { IS_LITE } from "@/lib/lite";
 import { toUnicodeEmail } from "@/lib/idn";
 
 interface NavItem {
@@ -222,7 +221,7 @@ export function NavigationRail({
   // removes the user's, so a pinned set still shows when custom apps are off.
   const visibleSidebarApps = useResolvedSidebarApps();
   const inboxUnread = mailboxes.find(m => m.role === "inbox")?.unreadEmails || 0;
-  const [isStalwartAdmin, setIsStalwartAdmin] = useState(false);
+  const isStalwartAdmin = useStalwartAdmin();
   const hasUpdate = useUpdateStore(selectHasUpdate);
   const updateSeverity = useUpdateStore((s) => s.status?.severity);
   const startUpdatePolling = useUpdateStore((s) => s.startPolling);
@@ -293,30 +292,6 @@ export function NavigationRail({
     };
   }, [logoutMenuOpen, logoutPopoverRef]);
 
-  useEffect(() => {
-    let cancelled = false;
-    const headers = getActiveAccountSlotHeaders();
-    // No admin console in the static Lite build.
-    if (IS_LITE || !headers['X-JMAP-Cookie-Slot']) return;
-    apiFetch('/api/admin/auth', { headers })
-      .then(res => res.json())
-      .then(data => {
-        if (cancelled || !data.stalwartAdmin) return;
-        setIsStalwartAdmin(true);
-        // Only "auto" mode may mint the admin session here; in "password"
-        // mode the shield leads to /admin/login instead (#870).
-        if (!data.authenticated && data.stalwartAutoLogin === true) {
-          // Pre-create admin session so /admin works even after full page navigation
-          apiFetch('/api/admin/auth', {
-            method: 'POST',
-            headers: { 'Content-Type': 'application/json', ...headers },
-            body: JSON.stringify({ stalwartAuth: true }),
-          }).catch(() => {});
-        }
-      })
-      .catch(() => {});
-    return () => { cancelled = true; };
-  }, []);
 
   const navItems: NavItem[] = [
     { id: "mail", icon: Mail, labelKey: "mail", href: "/", badge: inboxUnread },
diff --git a/hooks/__tests__/use-stalwart-admin.test.ts b/hooks/__tests__/use-stalwart-admin.test.ts
new file mode 100644
index 000000000..df6c31aca
--- /dev/null
+++ b/hooks/__tests__/use-stalwart-admin.test.ts
@@ -0,0 +1,51 @@
+import { describe, expect, it, vi, beforeEach } from 'vitest';
+import { renderHook, waitFor } from '@testing-library/react';
+
+const apiFetch = vi.hoisted(() => vi.fn());
+const slotHeaders = vi.hoisted(() => vi.fn());
+vi.mock('@/lib/browser-navigation', () => ({ apiFetch }));
+vi.mock('@/lib/auth/active-account-slot', () => ({ getActiveAccountSlotHeaders: slotHeaders }));
+
+import { useStalwartAdmin } from '../use-stalwart-admin';
+
+const answer = (body: Record<string, unknown>) =>
+  new Response(JSON.stringify(body), { status: 200, headers: { 'Content-Type': 'application/json' } });
+
+describe('useStalwartAdmin', () => {
+  beforeEach(() => {
+    apiFetch.mockReset();
+    slotHeaders.mockReturnValue({ 'X-JMAP-Cookie-Slot': '0' });
+  });
+
+  it('is true for a Stalwart admin and mints the session in auto mode', async () => {
+    apiFetch.mockResolvedValueOnce(answer({ stalwartAdmin: true, authenticated: false, stalwartAutoLogin: true }));
+    apiFetch.mockResolvedValueOnce(answer({}));
+
+    const { result } = renderHook(() => useStalwartAdmin());
+
+    await waitFor(() => expect(result.current).toBe(true));
+    expect(apiFetch).toHaveBeenLastCalledWith('/api/admin/auth', expect.objectContaining({ method: 'POST' }));
+  });
+
+  it('does not mint a session in password mode', async () => {
+    apiFetch.mockResolvedValueOnce(answer({ stalwartAdmin: true, authenticated: false, stalwartAutoLogin: false }));
+
+    const { result } = renderHook(() => useStalwartAdmin());
+
+    await waitFor(() => expect(result.current).toBe(true));
+    expect(apiFetch).toHaveBeenCalledTimes(1);
+  });
+
+  it('stays false for other users and without a login slot', async () => {
+    apiFetch.mockResolvedValueOnce(answer({ stalwartAdmin: false }));
+    const { result } = renderHook(() => useStalwartAdmin());
+    await waitFor(() => expect(apiFetch).toHaveBeenCalled());
+    expect(result.current).toBe(false);
+
+    apiFetch.mockReset();
+    slotHeaders.mockReturnValue({});
+    const { result: noSlot } = renderHook(() => useStalwartAdmin());
+    expect(noSlot.current).toBe(false);
+    expect(apiFetch).not.toHaveBeenCalled();
+  });
+});
diff --git a/hooks/use-stalwart-admin.ts b/hooks/use-stalwart-admin.ts
new file mode 100644
index 000000000..41fe01cec
--- /dev/null
+++ b/hooks/use-stalwart-admin.ts
@@ -0,0 +1,39 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { getActiveAccountSlotHeaders } from "@/lib/auth/active-account-slot";
+import { apiFetch } from "@/lib/browser-navigation";
+import { IS_LITE } from "@/lib/lite";
+
+/**
+ * Whether the signed-in user may open the Stalwart admin console. In "auto"
+ * mode the admin session is minted here as well, so /admin works even after a
+ * full page navigation; in "password" mode the console asks for it (#870).
+ */
+export function useStalwartAdmin(): boolean {
+  const [isStalwartAdmin, setIsStalwartAdmin] = useState(false);
+
+  useEffect(() => {
+    let cancelled = false;
+    const headers = getActiveAccountSlotHeaders();
+    // No admin console in the static Lite build.
+    if (IS_LITE || !headers['X-JMAP-Cookie-Slot']) return;
+    apiFetch('/api/admin/auth', { headers })
+      .then(res => res.json())
+      .then(data => {
+        if (cancelled || !data.stalwartAdmin) return;
+        setIsStalwartAdmin(true);
+        if (!data.authenticated && data.stalwartAutoLogin === true) {
+          apiFetch('/api/admin/auth', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json', ...headers },
+            body: JSON.stringify({ stalwartAuth: true }),
+          }).catch(() => {});
+        }
+      })
+      .catch(() => {});
+    return () => { cancelled = true; };
+  }, []);
+
+  return isStalwartAdmin;
+}

From 04cc00f89571c3e51761c97378ee24fc173ea69c Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Fri, 9 Oct 2026 08:35:17 +0200
Subject: [PATCH 13/23] fix(mountain-view): plain sheet under the conversation,
 round avatar button

Under the message the reply buttons sat on the tinted strip the default
layout uses for its quick reply, a different colour from the message
above them in the light theme. Mountain View now reads the whole
conversation on the page colour.

The account avatar in the top bar got a square highlight while every
other button there is round.
---
 components/email/email-viewer.tsx      | 6 ++++--
 components/layout/account-switcher.tsx | 4 +++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/components/email/email-viewer.tsx b/components/email/email-viewer.tsx
index c23f22eba..319cafdef 100644
--- a/components/email/email-viewer.tsx
+++ b/components/email/email-viewer.tsx
@@ -4066,8 +4066,10 @@ export function EmailViewer({
         </div>
       )}
 
-      {/* Email Content Area */}
-      <div className={cn("flex-1 overflow-auto overscroll-contain bg-muted/30", isMobile && !mvMobileViewer && "pb-[calc(3.25rem+env(safe-area-inset-bottom)/2)] sm:pb-0")}>
+      {/* Email Content Area. Mountain View reads the conversation on one plain
+          sheet, so the reply buttons under the message sit on the page colour
+          rather than on a tinted strip. */}
+      <div className={cn("flex-1 overflow-auto overscroll-contain", mvViewer || mvMobileViewer ? "bg-background" : "bg-muted/30", isMobile && !mvMobileViewer && "pb-[calc(3.25rem+env(safe-area-inset-bottom)/2)] sm:pb-0")}>
       <div className="min-h-full flex flex-col">
 
       {/* === SENDER INFO (Desktop) === */}
diff --git a/components/layout/account-switcher.tsx b/components/layout/account-switcher.tsx
index 6860f976b..6dd5c67d6 100644
--- a/components/layout/account-switcher.tsx
+++ b/components/layout/account-switcher.tsx
@@ -267,7 +267,9 @@ export function AccountSwitcher({
         data-testid="account-switcher"
         data-active-account-id={activeAccountId ?? undefined}
         className={cn(
-          "flex items-center gap-2 rounded-md transition-colors",
+          // Round under Mountain View, like every other button in its top bar.
+          "flex items-center gap-2 transition-colors",
+          mvPopover ? "rounded-full" : "rounded-md",
           variant !== "expanded"
             ? "justify-center w-10 h-10 hover:bg-muted"
             : "w-full px-2 py-1.5 hover:bg-muted text-start min-w-0",

From e8da96a6256b3748f6fd97f6c2b8e66880b4fa73 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Fri, 9 Oct 2026 09:05:07 +0200
Subject: [PATCH 14/23] fix(compose): keep body text from showing through the
 pinned toolbar

The formatting toolbar sticks to the top of the composer while the body
scrolls. Its background was bg-muted/30 with a backdrop blur, and in a
browser that skips backdrop-filter the body text showed sharp under the
buttons. The toolbar now uses the colour bg-muted/30 gives over the
page, made opaque: it looks the same at rest and hides the text when
pinned.
---
 components/email/rich-text-editor.tsx | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/components/email/rich-text-editor.tsx b/components/email/rich-text-editor.tsx
index bcfc2e887..5df37e1b5 100644
--- a/components/email/rich-text-editor.tsx
+++ b/components/email/rich-text-editor.tsx
@@ -426,13 +426,12 @@ export function RichTextEditor({
   return (
     <div className={cn("flex flex-col", hasError && "ring-2 ring-red-500 dark:ring-red-400 rounded", className)}>
       {/* Toolbar - sticky within the composer's scroll container so it stays
-          visible while editing long bodies. The background stays at main's
-          bg-muted/30 in every state - backdrop-blur has no visual effect while
-          the toolbar rests on the solid page background, and blurs body text
-          sliding underneath only once pinned, so pinned legibility needs no
-          extra opaque overlay (an always-on stronger overlay would read darker
-          than main even at rest). */}
-      <div className="sticky top-0 z-20 flex flex-wrap items-center gap-0.5 px-3 py-1.5 border-b border-border/50 bg-muted/30 backdrop-blur-sm">
+          visible while editing long bodies. Its background is the colour
+          bg-muted/30 gives over the page, made opaque: the same at rest, and
+          body text scrolling underneath stays hidden instead of showing
+          through, which a backdrop blur alone did not guarantee (browsers
+          that skip backdrop-filter drew the text sharp under the buttons). */}
+      <div className="sticky top-0 z-20 flex flex-wrap items-center gap-0.5 px-3 py-1.5 border-b border-border/50 bg-[color-mix(in_oklab,var(--color-muted)_30%,var(--color-background))]">
         {/* Font size - two baseline-aligned A's read as "size" at a glance;
             once a size is chosen the button shows that number instead. */}
         <div ref={fontSizeWrapperRef} className="relative">

From de6ae922d9004460a398b082759e2c9a3945a280 Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Fri, 9 Oct 2026 10:48:15 +0200
Subject: [PATCH 15/23] fix(push): use logical spacing in the all-accounts
 panel

pl-6 and mr-2 stayed on the left in right-to-left languages; ps-6 and
me-2 follow the reading direction.
---
 components/settings/multi-account-push.tsx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/components/settings/multi-account-push.tsx b/components/settings/multi-account-push.tsx
index d431a36b7..edf4711a1 100644
--- a/components/settings/multi-account-push.tsx
+++ b/components/settings/multi-account-push.tsx
@@ -91,7 +91,7 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
       </label>
       <ul className="space-y-2">
         {connected.map(account => <li key={account.id}>
-          <label className="flex items-start gap-2 pl-6 text-sm">
+          <label className="flex items-start gap-2 ps-6 text-sm">
             <input type="checkbox" className="mt-1" disabled={busy} checked={chosen.has(account.id)}
               onChange={e => toggle(account.id, e.target.checked)} />
             <span>
@@ -105,7 +105,7 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
       </ul>
       <div className="flex flex-wrap items-center gap-2">
         <Button type="button" onClick={() => void run('enable')} disabled={busy || !chosen.size}>
-          {busy && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}{t('enable_selected')}
+          {busy && <Loader2 className="me-2 h-4 w-4 animate-spin" />}{t('enable_selected')}
         </Button>
         <Button type="button" variant="outline" onClick={() => void run('disable')} disabled={busy || !chosen.size}>
           {t('disable_selected')}

From 9560a8b74fd1e8f05a419434330e6d9f94352c2f Mon Sep 17 00:00:00 2001
From: lucamzanon <luca.m.zanon@gmail.com>
Date: Fri, 9 Oct 2026 10:54:38 +0200
Subject: [PATCH 16/23] feat: optional encrypted backup of the account list

Users with several accounts can save the list of accounts in their browser
(address, server, label, colour) on the webmail server and bring it back on
another device. The list is encrypted in the browser with a password the user
chooses (PBKDF2-SHA-256, 600,000 iterations, AES-256-GCM, owner bound as
additional data); the server stores only the envelope, one file per owner
under SETTINGS_DATA_DIR/account-archives. No mailbox passwords are included.

Off by default behind the admin feature gate accountArchiveEnabled, pinned
off in Lite. Every method of /api/account-archive needs a session cookie of
the owner, matched without regard to case, whose credential is checked
against the mail server on each call; listing included.

Restored accounts this browser lacks are listed as awaiting sign-in: they
survive a reload, and opening one leads to the sign-in form with the address
filled in. Accounts already present get their archived label and colour.
---
 app/(main)/[locale]/login/page.tsx            |   3 +-
 app/(main)/admin/_tabs/policy.tsx             |   1 +
 app/api/account-archive/route.ts              |  87 +++++++++++++
 .../account-archive-settings.test.tsx         |  77 +++++++++++
 .../settings/account-archive-settings.tsx     | 123 ++++++++++++++++++
 components/settings/account-settings.tsx      |   6 +
 lib/__tests__/account-archive-route.test.ts   | 100 ++++++++++++++
 lib/__tests__/account-archive.test.ts         |  57 ++++++++
 lib/__tests__/lite-config.test.ts             |   3 +-
 lib/account-archive-client.ts                 |  63 +++++++++
 lib/account-archive-storage.ts                |  41 ++++++
 lib/account-archive.ts                        |  97 ++++++++++++++
 lib/admin/types.ts                            |   3 +
 lib/lite-config.ts                            |   2 +
 locales/ar/common.json                        |  27 ++++
 locales/ca/common.json                        |  27 ++++
 locales/cs/common.json                        |  27 ++++
 locales/da/common.json                        |  27 ++++
 locales/de/common.json                        |  27 ++++
 locales/en/common.json                        |  27 ++++
 locales/es/common.json                        |  27 ++++
 locales/fa/common.json                        |  27 ++++
 locales/fr/common.json                        |  27 ++++
 locales/he/common.json                        |  27 ++++
 locales/hu/common.json                        |  27 ++++
 locales/it/common.json                        |  27 ++++
 locales/ja/common.json                        |  27 ++++
 locales/ko/common.json                        |  27 ++++
 locales/lv/common.json                        |  27 ++++
 locales/mn/common.json                        |  27 ++++
 locales/nb/common.json                        |  27 ++++
 locales/nl/common.json                        |  27 ++++
 locales/pl/common.json                        |  27 ++++
 locales/pt/common.json                        |  27 ++++
 locales/ro/common.json                        |  27 ++++
 locales/ru/common.json                        |  27 ++++
 locales/sk/common.json                        |  27 ++++
 locales/tr/common.json                        |  27 ++++
 locales/uk/common.json                        |  27 ++++
 locales/zh-TW/common.json                     |  27 ++++
 locales/zh/common.json                        |  27 ++++
 scripts/lite/lib.mjs                          |   2 +
 .../auth-store-archive-restore.test.ts        |  97 ++++++++++++++
 stores/account-store.ts                       |   7 +
 stores/auth-store.ts                          |   8 ++
 45 files changed, 1504 insertions(+), 2 deletions(-)
 create mode 100644 app/api/account-archive/route.ts
 create mode 100644 components/settings/__tests__/account-archive-settings.test.tsx
 create mode 100644 components/settings/account-archive-settings.tsx
 create mode 100644 lib/__tests__/account-archive-route.test.ts
 create mode 100644 lib/__tests__/account-archive.test.ts
 create mode 100644 lib/account-archive-client.ts
 create mode 100644 lib/account-archive-storage.ts
 create mode 100644 lib/account-archive.ts
 create mode 100644 stores/__tests__/auth-store-archive-restore.test.ts

diff --git a/app/(main)/[locale]/login/page.tsx b/app/(main)/[locale]/login/page.tsx
index 62ec0967a..413ab869a 100644
--- a/app/(main)/[locale]/login/page.tsx
+++ b/app/(main)/[locale]/login/page.tsx
@@ -168,7 +168,8 @@ function LoginPageContent() {
     : undefined;
 
   const [formData, setFormData] = useState({
-    username: "",
+    // An account restored from the list backup opens this form with its address.
+    username: isAddAccountMode ? searchParams.get("username") ?? "" : "",
     password: "",
   });
   const [jmapEndpoint, setJmapEndpoint] = useState("");
diff --git a/app/(main)/admin/_tabs/policy.tsx b/app/(main)/admin/_tabs/policy.tsx
index bab81c8ad..8d59efcb4 100644
--- a/app/(main)/admin/_tabs/policy.tsx
+++ b/app/(main)/admin/_tabs/policy.tsx
@@ -38,6 +38,7 @@ const FEATURE_GATE_LABELS: Partial<Record<keyof FeatureGates, { label: string; d
   crossStarredViewEnabled: { label: 'Unified Mailbox: Starred', description: 'Allow a "Starred" entry in the Unified Mailbox section that lists flagged/starred mail across the account and its shared folders (or every account when the cross-account sub-option is on). Honors the user\'s folder selection. Requires the matching per-user toggle in Settings → Appearance.' },
   crossAllViewEnabled: { label: 'Unified Mailbox: All Mail', description: 'Allow an "All mail" entry in the Unified Mailbox section that lists all mail across the account and its shared folders (or every account when the cross-account sub-option is on). Honors the user\'s folder selection. Requires the matching per-user toggle in Settings → Appearance.' },
   unifiedCrossAccountEnabled: { label: 'Unified Mailbox: Cross-account', description: 'Allow users to expand the Unified Mailbox beyond the active account boundary so its lists merge across every logged-in account. When off, the Unified Mailbox stays within the active account and its shared folders.' },
+  accountArchiveEnabled: { label: 'Account List Backup', description: 'Let users save their list of accounts (address, server, label, colour) on this server, encrypted in the browser with a password of their choice, and restore it on another device. No mailbox passwords are stored. Archives live in SETTINGS_DATA_DIR/account-archives; requires SESSION_SECRET.' },
 };
 
 const RESTRICTABLE_SETTINGS = [
diff --git a/app/api/account-archive/route.ts b/app/api/account-archive/route.ts
new file mode 100644
index 000000000..c17b67e18
--- /dev/null
+++ b/app/api/account-archive/route.ts
@@ -0,0 +1,87 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { cookies } from 'next/headers';
+import { configManager } from '@/lib/admin/config-manager';
+import { hasSessionSecret } from '@/lib/auth/session-secret';
+import { readStalwartAuthContextFromStore } from '@/lib/stalwart/auth-context';
+import { assertBasicAuthMatchesUsername, verifyJmapAuth } from '@/lib/auth/verify-jmap-auth';
+import { parseJmapServers, resolveTrustedJmapUrl } from '@/lib/admin/jmap-servers';
+import { rejectCrossOriginRequest } from '@/lib/security/same-origin';
+import { MAX_ACCOUNT_SLOTS } from '@/lib/account-utils';
+import { archiveIdentity, parseArchiveEnvelope, ARCHIVE_MAX_BYTES, type ArchiveOwner } from '@/lib/account-archive';
+import { deleteArchive, loadArchive, saveArchive } from '@/lib/account-archive-storage';
+
+export const runtime = 'nodejs';
+
+const reply = (data: unknown, status = 200) => NextResponse.json(data, {
+  status, headers: { 'Cache-Control': 'no-store' },
+});
+
+/**
+ * The owner whose archive this request may touch, or the response refusing it.
+ *
+ * A session cookie alone is not enough: cookies for admin-configured servers
+ * can outlive the credential inside them. So the credential in the matching
+ * slot is checked against the mail server on every call, and listing is held
+ * to the same rule as writing, since the ciphertext is what an offline
+ * password guess would need.
+ */
+async function verifiedOwner(request: NextRequest): Promise<ArchiveOwner | NextResponse> {
+  await configManager.ensureLoaded();
+  if (!configManager.getPolicy().features.accountArchiveEnabled || !hasSessionSecret()) return reply({ error: 'disabled' }, 404);
+  const denied = reply({ error: 'owner_signin_required' }, 403);
+  let claimed: string;
+  try {
+    claimed = archiveIdentity({
+      username: request.headers.get('x-archive-username') ?? '',
+      serverUrl: request.headers.get('x-archive-server') ?? '',
+    });
+  } catch { return denied; }
+  const store = await cookies();
+  for (let slot = 0; slot < MAX_ACCOUNT_SLOTS; slot++) {
+    const ctx = readStalwartAuthContextFromStore(store, slot);
+    if (!ctx) continue;
+    try { if (archiveIdentity(ctx) !== claimed) continue; } catch { continue; }
+    try {
+      // The cookie's own username, not the header's: the two may differ in case.
+      assertBasicAuthMatchesUsername(ctx.authHeader, ctx.username);
+      const trusted = resolveTrustedJmapUrl(ctx.serverUrl,
+        configManager.get<string>('jmapServerUrl', ''),
+        parseJmapServers(configManager.get<unknown>('jmapServers', [])));
+      await verifyJmapAuth(ctx.serverUrl, ctx.authHeader, { trusted: !!trusted });
+    } catch { return denied; }
+    return { username: ctx.accountName ?? ctx.username, serverUrl: ctx.serverUrl };
+  }
+  return denied;
+}
+
+export async function GET(request: NextRequest) {
+  const owner = await verifiedOwner(request);
+  if (owner instanceof NextResponse) return owner;
+  try { return reply({ envelope: await loadArchive(owner) }); }
+  catch { return reply({ error: 'storage_failed' }, 500); }
+}
+
+export async function PUT(request: NextRequest) {
+  const crossOrigin = rejectCrossOriginRequest(request);
+  if (crossOrigin) return crossOrigin;
+  const owner = await verifiedOwner(request);
+  if (owner instanceof NextResponse) return owner;
+  if (Number(request.headers.get('content-length') ?? 0) > ARCHIVE_MAX_BYTES) return reply({ error: 'too_large' }, 413);
+  let envelope;
+  try {
+    const text = await request.text();
+    if (text.length > ARCHIVE_MAX_BYTES) return reply({ error: 'too_large' }, 413);
+    envelope = parseArchiveEnvelope((JSON.parse(text) as { envelope?: unknown })?.envelope);
+  } catch { return reply({ error: 'invalid_archive' }, 400); }
+  try { await saveArchive(owner, envelope); return reply({ ok: true }); }
+  catch { return reply({ error: 'storage_failed' }, 500); }
+}
+
+export async function DELETE(request: NextRequest) {
+  const crossOrigin = rejectCrossOriginRequest(request);
+  if (crossOrigin) return crossOrigin;
+  const owner = await verifiedOwner(request);
+  if (owner instanceof NextResponse) return owner;
+  try { await deleteArchive(owner); return reply({ ok: true }); }
+  catch { return reply({ error: 'storage_failed' }, 500); }
+}
diff --git a/components/settings/__tests__/account-archive-settings.test.tsx b/components/settings/__tests__/account-archive-settings.test.tsx
new file mode 100644
index 000000000..eabb4737a
--- /dev/null
+++ b/components/settings/__tests__/account-archive-settings.test.tsx
@@ -0,0 +1,77 @@
+import { fireEvent, render, screen, waitFor } from '@testing-library/react';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { AccountArchiveSettings } from '../account-archive-settings';
+import { useAccountStore } from '@/stores/account-store';
+import { useAuthStore } from '@/stores/auth-store';
+
+const mocks = vi.hoisted(() => ({ apiFetch: vi.fn(), stored: null as unknown }));
+
+vi.mock('next-intl', () => {
+  const t = (key: string, values?: Record<string, unknown>) => values ? `${key} ${JSON.stringify(values)}` : key;
+  return { useTranslations: () => t, useLocale: () => 'en' };
+});
+vi.mock('@/lib/browser-navigation', async (importOriginal) => ({
+  ...(await importOriginal<typeof import('@/lib/browser-navigation')>()),
+  apiFetch: mocks.apiFetch,
+}));
+
+const owner = { username: 'owner@x.test', serverUrl: 'https://mail.x.test' };
+const account = {
+  id: 'owner@x.test@mail.x.test', label: 'Work', ...owner, authMode: 'basic' as const, rememberMe: true, cookieSlot: 0,
+  displayName: 'Work', email: owner.username, isConnected: true, hasError: false, lastLoginAt: 1, avatarColor: '#2563eb', isDefault: true,
+};
+
+beforeEach(() => {
+  mocks.stored = null;
+  mocks.apiFetch.mockReset().mockImplementation(async (_url: string, init: RequestInit = {}) => {
+    if (init.method === 'PUT') mocks.stored = JSON.parse(String(init.body)).envelope;
+    if (init.method === 'DELETE') mocks.stored = null;
+    return new Response(JSON.stringify(init.method ? { ok: true } : { envelope: mocks.stored }), { status: 200 });
+  });
+  useAuthStore.setState(owner);
+  useAccountStore.setState({ accounts: [account] as never, activeAccountId: account.id, defaultAccountId: account.id });
+});
+
+const fill = (label: string, value: string) => fireEvent.change(screen.getByLabelText(label), { target: { value } });
+
+describe('AccountArchiveSettings', () => {
+  it('saves the list encrypted, then restores it on a browser that lacks the accounts', async () => {
+    render(<AccountArchiveSettings />);
+    await screen.findByText(/^status_none/);
+    fireEvent.click(screen.getByRole('button', { name: 'save' }));
+    fill('password', 'a long backup password');
+    fill('confirm', 'a different password!');
+    fireEvent.submit(screen.getByLabelText('confirm').closest('form')!);
+    expect(await screen.findByRole('alert')).toHaveTextContent('errors.mismatch');
+    expect(mocks.apiFetch).not.toHaveBeenCalledWith('/api/account-archive', expect.objectContaining({ method: 'PUT' }));
+
+    fill('confirm', 'a long backup password');
+    fireEvent.submit(screen.getByLabelText('confirm').closest('form')!);
+    expect(await screen.findByRole('status', {}, { timeout: 5000 })).toHaveTextContent('saved {"count":1}');
+    const [, init] = mocks.apiFetch.mock.calls.find(([, i]) => i?.method === 'PUT')!;
+    expect(init.headers).toMatchObject({ 'x-archive-username': owner.username, 'x-archive-server': owner.serverUrl });
+    expect(String(init.body)).not.toContain('x.test');
+    expect(String(init.body)).not.toContain('Work');
+
+    // Another browser: same owner signed in, the other account not there yet.
+    useAccountStore.setState({ accounts: [{ ...account, label: 'Renamed', avatarColor: '#000000' }] as never });
+    fireEvent.click(screen.getByRole('button', { name: 'restore' }));
+    fill('password', 'a long backup password');
+    fireEvent.submit(screen.getByLabelText('password').closest('form')!);
+    await waitFor(() => expect(screen.getByRole('status')).toHaveTextContent('restored'), { timeout: 5000 });
+    expect(useAccountStore.getState().accounts[0]).toMatchObject({ label: 'Work', avatarColor: '#2563eb' });
+  });
+
+  it('reports a wrong restore password', async () => {
+    render(<AccountArchiveSettings />);
+    fireEvent.click(await screen.findByRole('button', { name: 'save' }));
+    fill('password', 'a long backup password');
+    fill('confirm', 'a long backup password');
+    fireEvent.submit(screen.getByLabelText('confirm').closest('form')!);
+    await screen.findByRole('status', {}, { timeout: 5000 });
+    fireEvent.click(screen.getByRole('button', { name: 'restore' }));
+    fill('password', 'not the password');
+    fireEvent.submit(screen.getByLabelText('password').closest('form')!);
+    expect(await screen.findByRole('alert', {}, { timeout: 5000 })).toHaveTextContent('errors.unlock_failed');
+  });
+});
diff --git a/components/settings/account-archive-settings.tsx b/components/settings/account-archive-settings.tsx
new file mode 100644
index 000000000..9a4215502
--- /dev/null
+++ b/components/settings/account-archive-settings.tsx
@@ -0,0 +1,123 @@
+"use client";
+
+import { useEffect, useId, useState } from 'react';
+import { useTranslations } from 'next-intl';
+import { Button } from '@/components/ui/button';
+import { Input } from '@/components/ui/input';
+import { useAuthStore } from '@/stores/auth-store';
+import { decryptArchive, encryptArchive, ARCHIVE_MIN_PASSWORD, type ArchiveOwner } from '@/lib/account-archive';
+import { collectAccounts, fetchArchive, putArchive, removeArchive, restoreAccounts } from '@/lib/account-archive-client';
+import { toUnicodeEmail } from '@/lib/idn';
+import { SettingsSection } from './settings-section';
+
+const KNOWN_ERRORS = ['mismatch', 'password_length', 'unlock_failed', 'owner_signin_required', 'https_required'];
+
+/** Save this browser's account list, encrypted, under the active account; restore it on another device. */
+export function AccountArchiveSettings() {
+  const t = useTranslations('settings.account.backup');
+  const id = useId();
+  const username = useAuthStore(s => s.username);
+  const serverUrl = useAuthStore(s => s.serverUrl);
+  const [saved, setSaved] = useState<boolean | null>(null);
+  const [mode, setMode] = useState<'save' | 'restore' | null>(null);
+  const [password, setPassword] = useState('');
+  const [confirmation, setConfirmation] = useState('');
+  const [busy, setBusy] = useState(false);
+  const [message, setMessage] = useState<{ error: boolean; text: string } | null>(null);
+  const owner: ArchiveOwner | null = username && serverUrl ? { username, serverUrl } : null;
+
+  useEffect(() => {
+    setSaved(null);
+    if (!username || !serverUrl) return;
+    let cancelled = false;
+    fetchArchive({ username, serverUrl })
+      .then(envelope => { if (!cancelled) setSaved(envelope !== null); })
+      .catch(() => { if (!cancelled) setSaved(false); });
+    return () => { cancelled = true; };
+  }, [username, serverUrl]);
+
+  if (!owner) return null;
+
+  const open = (next: 'save' | 'restore' | null) => {
+    setMode(next); setPassword(''); setConfirmation(''); setMessage(null);
+  };
+  const run = async (action: () => Promise<string>) => {
+    setBusy(true); setMessage(null);
+    try {
+      const text = await action();
+      open(null);
+      setMessage({ error: false, text });
+    }
+    catch (err) {
+      const code = err instanceof Error ? err.message : '';
+      setMessage({ error: true, text: t(`errors.${KNOWN_ERRORS.includes(code) ? code : 'storage_failed'}`) });
+    } finally { setBusy(false); }
+  };
+
+  const save = () => run(async () => {
+    if (password !== confirmation) throw new Error('mismatch');
+    const accounts = collectAccounts();
+    await putArchive(owner, await encryptArchive(owner, accounts, password));
+    setSaved(true);
+    return t('saved', { count: accounts.length });
+  });
+  const restore = () => run(async () => {
+    const envelope = await fetchArchive(owner);
+    if (!envelope) { setSaved(false); throw new Error('storage_failed'); }
+    const result = restoreAccounts(await decryptArchive(owner, envelope, password));
+    return [t('restored', result), result.skipped ? t('skipped', { count: result.skipped }) : ''].join(' ').trim();
+  });
+  const remove = () => {
+    if (!window.confirm(t('delete_confirm'))) return;
+    void run(async () => { await removeArchive(owner); setSaved(false); return t('deleted'); });
+  };
+
+  return (
+    <SettingsSection title={t('title')} description={t('description')}>
+      <p className="text-sm text-muted-foreground">
+        {saved === null ? '…' : t(saved ? 'status_saved' : 'status_none', { account: toUnicodeEmail(owner.username) })}
+      </p>
+      {mode === null ? (
+        <div className="flex flex-wrap gap-2">
+          <Button type="button" size="sm" onClick={() => open('save')}>{t('save')}</Button>
+          {saved && <Button type="button" size="sm" variant="outline" onClick={() => open('restore')}>{t('restore')}</Button>}
+          {saved && <Button type="button" size="sm" variant="ghost" disabled={busy} onClick={remove}>{t('delete')}</Button>}
+        </div>
+      ) : (
+        <form
+          className="space-y-3 max-w-md"
+          onSubmit={e => { e.preventDefault(); void (mode === 'save' ? save() : restore()); }}
+        >
+          <label className="block text-sm font-medium" htmlFor={`${id}-password`}>{t('password')}</label>
+          <Input
+            id={`${id}-password`} type="password" value={password} required autoFocus
+            minLength={mode === 'save' ? ARCHIVE_MIN_PASSWORD : undefined}
+            autoComplete={mode === 'save' ? 'new-password' : 'current-password'}
+            aria-describedby={`${id}-hint`} onChange={e => setPassword(e.target.value)}
+          />
+          <p id={`${id}-hint`} className="text-xs text-muted-foreground">
+            {t(mode === 'save' ? 'password_hint' : 'restore_hint')}
+          </p>
+          {mode === 'save' && (
+            <>
+              <label className="block text-sm font-medium" htmlFor={`${id}-confirm`}>{t('confirm')}</label>
+              <Input
+                id={`${id}-confirm`} type="password" value={confirmation} required autoComplete="new-password"
+                onChange={e => setConfirmation(e.target.value)}
+              />
+            </>
+          )}
+          <div className="flex flex-wrap gap-2">
+            <Button type="submit" size="sm" disabled={busy}>{t(mode === 'save' ? 'save' : 'restore')}</Button>
+            <Button type="button" size="sm" variant="ghost" disabled={busy} onClick={() => open(null)}>{t('cancel')}</Button>
+          </div>
+        </form>
+      )}
+      {message && (
+        <p role={message.error ? 'alert' : 'status'} className={message.error ? 'text-sm text-destructive' : 'text-sm text-foreground'}>
+          {message.text}
+        </p>
+      )}
+    </SettingsSection>
+  );
+}
diff --git a/components/settings/account-settings.tsx b/components/settings/account-settings.tsx
index a0ddbcb95..92e17490a 100644
--- a/components/settings/account-settings.tsx
+++ b/components/settings/account-settings.tsx
@@ -15,6 +15,9 @@ import { useRouter } from '@/i18n/navigation';
 import { getMaxAccounts } from '@/lib/account-utils';
 import { formatFileSize, cn } from '@/lib/utils';
 import { toUnicodeDomain, toUnicodeEmail } from '@/lib/idn';
+import { IS_LITE } from '@/lib/lite';
+import { usePolicyStore } from '@/stores/policy-store';
+import { AccountArchiveSettings } from './account-archive-settings';
 
 function hostnameOf(serverUrl: string): string {
   try { return toUnicodeDomain(new URL(serverUrl).hostname); } catch { return serverUrl; }
@@ -38,6 +41,7 @@ export function AccountSettings() {
   const activeAccountId = useAuthStore((s) => s.activeAccountId);
   const switchAccount = useAuthStore((s) => s.switchAccount);
   const setManagedAccount = useManagedAccountStore((s) => s.setManagedAccount);
+  const archiveEnabled = usePolicyStore((s) => s.isFeatureEnabled('accountArchiveEnabled')) && !IS_LITE && !isDemoMode;
 
   // Shared/group accounts delegated to this session (excludes the user's own
   // primary account). These can be drilled into for scoped settings editing.
@@ -235,6 +239,8 @@ export function AccountSettings() {
         </SettingsSection>
       )}
 
+      {archiveEnabled && <AccountArchiveSettings />}
+
       {/* Shared / group accounts delegated to this session. Clicking one drills
           into a scoped settings view (filters, vacation, calendars, contacts). */}
       {sharedAccounts.length > 0 && (
diff --git a/lib/__tests__/account-archive-route.test.ts b/lib/__tests__/account-archive-route.test.ts
new file mode 100644
index 000000000..e52ed703e
--- /dev/null
+++ b/lib/__tests__/account-archive-route.test.ts
@@ -0,0 +1,100 @@
+// @vitest-environment node
+import { mkdtempSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest';
+import { NextRequest } from 'next/server';
+
+const mocks = vi.hoisted(() => ({
+  enabled: true, contexts: new Map<number, unknown>(), verify: vi.fn(),
+}));
+vi.mock('@/lib/admin/config-manager', () => ({ configManager: {
+  ensureLoaded: async () => {},
+  get: (_key: string, fallback: unknown) => fallback,
+  getPolicy: () => ({ features: { accountArchiveEnabled: mocks.enabled } }),
+} }));
+vi.mock('@/lib/auth/session-secret', () => ({ hasSessionSecret: () => true }));
+vi.mock('next/headers', () => ({ cookies: async () => ({}) }));
+vi.mock('@/lib/stalwart/auth-context', () => ({
+  readStalwartAuthContextFromStore: (_: unknown, slot: number) => mocks.contexts.get(slot) ?? null,
+}));
+vi.mock('@/lib/auth/verify-jmap-auth', async importOriginal => ({
+  ...await importOriginal<typeof import('@/lib/auth/verify-jmap-auth')>(), verifyJmapAuth: mocks.verify,
+}));
+
+const dataDir = mkdtempSync(path.join(tmpdir(), 'bw-account-archive-'));
+process.env.SETTINGS_DATA_DIR = dataDir;
+afterAll(() => rmSync(dataDir, { recursive: true, force: true }));
+
+import { DELETE, GET, PUT } from '@/app/api/account-archive/route';
+
+const owner = { username: 'owner@example.com', serverUrl: 'https://mail.example.com' };
+const envelope = { version: 1, iterations: 600000, salt: 'A'.repeat(22) + '==', iv: 'A'.repeat(16), ciphertext: 'A'.repeat(43) + '=' };
+const basic = (user: string) => 'Basic ' + Buffer.from(`${user}:secret`).toString('base64');
+
+function request(method: string, body?: unknown, headers: Record<string, string> = {}) {
+  return new NextRequest('https://webmail.example.com/api/account-archive', {
+    method,
+    headers: { 'x-archive-username': owner.username, 'x-archive-server': owner.serverUrl, 'content-type': 'application/json', ...headers },
+    ...(body === undefined ? {} : { body: JSON.stringify(body) }),
+  });
+}
+const signIn = (username = owner.username, slot = 3) => {
+  mocks.contexts.set(slot, { username, serverUrl: owner.serverUrl, authHeader: basic(username) });
+};
+
+beforeEach(() => {
+  mocks.enabled = true;
+  mocks.contexts.clear();
+  mocks.verify.mockReset().mockResolvedValue(owner.serverUrl);
+});
+
+describe('account archive API', () => {
+  it('is off unless the admin enables it', async () => {
+    mocks.enabled = false;
+    signIn();
+    expect((await GET(request('GET'))).status).toBe(404);
+    expect((await PUT(request('PUT', { envelope }))).status).toBe(404);
+    expect((await DELETE(request('DELETE'))).status).toBe(404);
+  });
+
+  it('refuses every method without a verified session of the owner', async () => {
+    for (const call of [() => GET(request('GET')), () => PUT(request('PUT', { envelope })), () => DELETE(request('DELETE'))]) {
+      expect((await call()).status).toBe(403);
+    }
+    // Another user's session, or a credential that does not match its cookie.
+    mocks.contexts.set(0, { ...owner, username: 'someone@example.com', authHeader: basic('someone@example.com') });
+    mocks.contexts.set(1, { ...owner, authHeader: basic('someone@example.com') });
+    expect((await GET(request('GET'))).status).toBe(403);
+    // The owner's cookie whose credential the mail server no longer accepts.
+    mocks.contexts.clear();
+    signIn();
+    mocks.verify.mockRejectedValue(new Error('401'));
+    expect((await GET(request('GET'))).status).toBe(403);
+    expect((await PUT(request('PUT', { envelope }))).status).toBe(403);
+  });
+
+  it('stores, returns and deletes the envelope for the verified owner, in any case', async () => {
+    signIn('Owner@Example.com');
+    let res = await GET(request('GET'));
+    expect(res.status).toBe(200);
+    expect(res.headers.get('Cache-Control')).toBe('no-store');
+    expect((await res.json()).envelope).toBeNull();
+
+    res = await PUT(request('PUT', { envelope: { ...envelope, password: 'forbidden' }, accounts: ['forbidden'] }));
+    expect(res.status).toBe(200);
+    expect(mocks.verify).toHaveBeenCalledWith(owner.serverUrl, basic('Owner@Example.com'), { trusted: false });
+    expect((await (await GET(request('GET'))).json()).envelope).toEqual(envelope);
+
+    expect((await DELETE(request('DELETE'))).status).toBe(200);
+    expect((await (await GET(request('GET'))).json()).envelope).toBeNull();
+  });
+
+  it('rejects cross-site writes, malformed envelopes and oversized bodies', async () => {
+    signIn();
+    expect((await PUT(request('PUT', { envelope }, { 'sec-fetch-site': 'cross-site' }))).status).toBe(403);
+    expect((await DELETE(request('DELETE', undefined, { 'sec-fetch-site': 'cross-site' }))).status).toBe(403);
+    expect((await PUT(request('PUT', { envelope: { ...envelope, iterations: 1 } }))).status).toBe(400);
+    expect((await PUT(request('PUT', { envelope: { ...envelope, ciphertext: 'A'.repeat(70000) } }))).status).toBe(413);
+  });
+});
diff --git a/lib/__tests__/account-archive.test.ts b/lib/__tests__/account-archive.test.ts
new file mode 100644
index 000000000..2c5bc6048
--- /dev/null
+++ b/lib/__tests__/account-archive.test.ts
@@ -0,0 +1,57 @@
+// @vitest-environment node
+import { describe, expect, it } from 'vitest';
+import {
+  archiveIdentity, decryptArchive, encryptArchive, parseArchiveEnvelope, parseArchivedAccounts, type ArchivedAccount,
+} from '@/lib/account-archive';
+
+const owner = { username: 'owner@example.com', serverUrl: 'https://mail.example.com' };
+const accounts: ArchivedAccount[] = [
+  { username: 'owner@example.com', serverUrl: 'https://mail.example.com', label: 'Work', avatarColor: '#2563eb' },
+  { username: 'me@other.example', serverUrl: 'https://jmap.other.example/', label: 'Home', avatarColor: '#16a34a' },
+];
+const password = 'correct horse battery';
+
+describe('account archive encryption', () => {
+  it('round-trips the account list and leaves only ciphertext in the envelope', async () => {
+    const envelope = await encryptArchive(owner, accounts, password);
+    expect(JSON.stringify(envelope)).not.toContain('example');
+    expect(JSON.stringify(envelope)).not.toContain('Work');
+    expect(await decryptArchive(owner, envelope, password)).toEqual([
+      accounts[0], { ...accounts[1], serverUrl: 'https://jmap.other.example' },
+    ]);
+  });
+
+  it('refuses a wrong password and an envelope moved to another owner', async () => {
+    const envelope = await encryptArchive(owner, accounts, password);
+    await expect(decryptArchive(owner, envelope, 'wrong password!')).rejects.toThrow('unlock_failed');
+    await expect(decryptArchive({ ...owner, username: 'thief@example.com' }, envelope, password)).rejects.toThrow('unlock_failed');
+  });
+
+  it('treats the owner username without regard to case', async () => {
+    const envelope = await encryptArchive({ ...owner, username: 'Owner@Example.com' }, accounts, password);
+    expect(await decryptArchive(owner, envelope, password)).toHaveLength(2);
+    expect(archiveIdentity({ ...owner, username: 'OWNER@example.com' })).toBe(archiveIdentity(owner));
+    expect(archiveIdentity({ ...owner, serverUrl: 'https://mail.example.com/' })).toBe(archiveIdentity(owner));
+  });
+
+  it('demands a password of at least 10 characters', async () => {
+    await expect(encryptArchive(owner, accounts, 'short')).rejects.toThrow('password_length');
+  });
+
+  it('never carries a password or any other extra field', async () => {
+    const withSecrets = accounts.map(a => ({ ...a, password: 'mailbox-secret', token: 't' }));
+    const envelope = await encryptArchive(owner, withSecrets, password);
+    const restored = await decryptArchive(owner, envelope, password);
+    expect(JSON.stringify(restored)).not.toContain('mailbox-secret');
+    expect(Object.keys(restored[0]).sort()).toEqual(['avatarColor', 'label', 'serverUrl', 'username']);
+  });
+
+  it('rejects malformed lists and envelopes', async () => {
+    expect(() => parseArchivedAccounts([])).toThrow('invalid_archive');
+    expect(() => parseArchivedAccounts([{ ...accounts[0], avatarColor: 'red' }])).toThrow('invalid_archive');
+    const envelope = await encryptArchive(owner, accounts, password);
+    expect(parseArchiveEnvelope({ ...envelope, extra: 'x' })).toEqual(envelope);
+    expect(() => parseArchiveEnvelope({ ...envelope, iterations: 1000 })).toThrow('invalid_archive');
+    expect(() => parseArchiveEnvelope({ ...envelope, iv: 'AAAA' })).toThrow('invalid_archive');
+  });
+});
diff --git a/lib/__tests__/lite-config.test.ts b/lib/__tests__/lite-config.test.ts
index e347d1b80..508be6a11 100644
--- a/lib/__tests__/lite-config.test.ts
+++ b/lib/__tests__/lite-config.test.ts
@@ -103,13 +103,14 @@ describe('applyLitePolicy (policy.json for the static build)', () => {
 
   it('honours deployer gates and restrictions but never re-enables plugins', () => {
     const policy = applyLitePolicy({
-      features: { pluginsEnabled: true, sidebarAppsEnabled: true, calendarEnabled: false },
+      features: { pluginsEnabled: true, sidebarAppsEnabled: true, calendarEnabled: false, accountArchiveEnabled: true },
       restrictions: { theme: { locked: true, value: 'dark' } },
       forceEnabledPlugins: ['evil'],
       defaultSidebarApps: [{ id: 'x' }],
     });
     expect(policy.features.pluginsEnabled).toBe(false);
     expect(policy.features.sidebarAppsEnabled).toBe(false);
+    expect(policy.features.accountArchiveEnabled).toBe(false);
     expect(policy.features.calendarEnabled).toBe(false);
     expect(policy.restrictions.theme).toEqual({ locked: true, value: 'dark' });
     expect(policy.forceEnabledPlugins).toEqual([]);
diff --git a/lib/account-archive-client.ts b/lib/account-archive-client.ts
new file mode 100644
index 000000000..2ca00f455
--- /dev/null
+++ b/lib/account-archive-client.ts
@@ -0,0 +1,63 @@
+import { apiFetch } from '@/lib/browser-navigation';
+import { IS_LITE } from '@/lib/lite';
+import { generateAccountId, getMaxAccounts } from '@/lib/account-utils';
+import { useAccountStore } from '@/stores/account-store';
+import type { ArchiveEnvelope, ArchiveOwner, ArchivedAccount } from './account-archive';
+
+async function request(owner: ArchiveOwner, init: RequestInit = {}): Promise<{ envelope?: ArchiveEnvelope | null }> {
+  // The archive lives on this app's server; the static Lite build has none.
+  if (IS_LITE) throw new Error('disabled');
+  const res = await apiFetch('/api/account-archive', {
+    cache: 'no-store', ...init,
+    headers: {
+      'x-archive-username': owner.username, 'x-archive-server': owner.serverUrl,
+      ...(init.body ? { 'Content-Type': 'application/json' } : {}),
+    },
+  });
+  const body = await res.json().catch(() => ({}));
+  if (!res.ok) throw new Error(typeof body.error === 'string' ? body.error : 'storage_failed');
+  return body;
+}
+
+export async function fetchArchive(owner: ArchiveOwner): Promise<ArchiveEnvelope | null> {
+  return (await request(owner)).envelope ?? null;
+}
+export async function putArchive(owner: ArchiveOwner, envelope: ArchiveEnvelope): Promise<void> {
+  await request(owner, { method: 'PUT', body: JSON.stringify({ envelope }) });
+}
+export async function removeArchive(owner: ArchiveOwner): Promise<void> {
+  await request(owner, { method: 'DELETE' });
+}
+
+/** This browser's accounts as the archive keeps them: no credentials of any kind. */
+export function collectAccounts(): ArchivedAccount[] {
+  return useAccountStore.getState().accounts.map(a => ({
+    username: a.username, serverUrl: a.serverUrl, label: a.label, avatarColor: a.avatarColor,
+  }));
+}
+
+/**
+ * Adds the archived accounts this browser lacks, each waiting for its own
+ * sign-in, and gives the ones it has their archived label and colour.
+ */
+export function restoreAccounts(archived: ArchivedAccount[]): { added: number; updated: number; skipped: number } {
+  const store = useAccountStore.getState();
+  let added = 0, updated = 0, skipped = 0;
+  for (const entry of archived) {
+    const id = generateAccountId(entry.username, entry.serverUrl);
+    if (store.getAccountById(id)) {
+      store.updateAccount(id, { label: entry.label, avatarColor: entry.avatarColor });
+      updated++;
+      continue;
+    }
+    if (useAccountStore.getState().accounts.length >= getMaxAccounts()) { skipped++; continue; }
+    store.addAccount({
+      username: entry.username, serverUrl: entry.serverUrl, authMode: 'basic', rememberMe: false,
+      label: entry.label, displayName: entry.label, email: entry.username, lastLoginAt: 0,
+      isConnected: false, hasError: true, isDefault: false, awaitingSignIn: true,
+    });
+    store.updateAccount(id, { avatarColor: entry.avatarColor });
+    added++;
+  }
+  return { added, updated, skipped };
+}
diff --git a/lib/account-archive-storage.ts b/lib/account-archive-storage.ts
new file mode 100644
index 000000000..c27c6d58a
--- /dev/null
+++ b/lib/account-archive-storage.ts
@@ -0,0 +1,41 @@
+import { createHash, randomBytes } from 'node:crypto';
+import { mkdir, open, readFile, rename, unlink } from 'node:fs/promises';
+import path from 'node:path';
+import { archiveIdentity, parseArchiveEnvelope, type ArchiveEnvelope, type ArchiveOwner } from './account-archive';
+
+/** One file per owner: `SETTINGS_DATA_DIR/account-archives/<sha256 of the owner>.json`. */
+function archiveDir(): string {
+  return path.join(process.env.SETTINGS_DATA_DIR || path.join(process.cwd(), 'data', 'settings'), 'account-archives');
+}
+function archivePath(owner: ArchiveOwner): string {
+  return path.join(archiveDir(), createHash('sha256').update(archiveIdentity(owner)).digest('hex') + '.json');
+}
+
+export async function loadArchive(owner: ArchiveOwner): Promise<ArchiveEnvelope | null> {
+  try { return parseArchiveEnvelope(JSON.parse(await readFile(archivePath(owner), 'utf8'))); }
+  catch (err) {
+    if ((err as NodeJS.ErrnoException).code === 'ENOENT') return null;
+    throw err;
+  }
+}
+
+/** Replaces the owner's archive atomically: a reader sees the old file or the new one, never half of it. */
+export async function saveArchive(owner: ArchiveOwner, envelope: ArchiveEnvelope): Promise<void> {
+  const target = archivePath(owner);
+  const temporary = `${target}.${randomBytes(8).toString('hex')}.tmp`;
+  await mkdir(archiveDir(), { recursive: true, mode: 0o700 });
+  try {
+    const file = await open(temporary, 'wx', 0o600);
+    try { await file.writeFile(JSON.stringify(parseArchiveEnvelope(envelope))); await file.sync(); }
+    finally { await file.close(); }
+    await rename(temporary, target);
+  } finally {
+    await unlink(temporary).catch(() => {});
+  }
+}
+
+export async function deleteArchive(owner: ArchiveOwner): Promise<void> {
+  await unlink(archivePath(owner)).catch(err => {
+    if ((err as NodeJS.ErrnoException).code !== 'ENOENT') throw err;
+  });
+}
diff --git a/lib/account-archive.ts b/lib/account-archive.ts
new file mode 100644
index 000000000..fa64a505f
--- /dev/null
+++ b/lib/account-archive.ts
@@ -0,0 +1,97 @@
+/**
+ * Encrypted list of a user's accounts, kept on the server so another browser
+ * can bring the same accounts back. Encryption happens in the browser with a
+ * password the user chooses; the server only ever sees the envelope.
+ *
+ * The list holds no mailbox passwords: each restored account is signed in to
+ * by hand.
+ */
+
+export interface ArchiveOwner { username: string; serverUrl: string }
+export interface ArchivedAccount extends ArchiveOwner { label: string; avatarColor: string }
+export interface ArchiveEnvelope {
+  version: 1;
+  iterations: typeof ARCHIVE_ITERATIONS;
+  salt: string;
+  iv: string;
+  ciphertext: string;
+}
+
+export const ARCHIVE_ITERATIONS = 600000;
+export const ARCHIVE_MAX_BYTES = 64 * 1024;
+export const ARCHIVE_MAX_ACCOUNTS = 50;
+export const ARCHIVE_MIN_PASSWORD = 10;
+
+const trimUrl = (url: string) => url.replace(/\/+$/, '');
+
+/**
+ * One owner however the username is cased: `Lu@example.com` and
+ * `lu@example.com` sign in to the same mailbox, so they share the archive.
+ */
+export function archiveIdentity(owner: ArchiveOwner): string {
+  if (typeof owner?.username !== 'string' || !owner.username.trim() || owner.username.length > 320
+    || typeof owner.serverUrl !== 'string' || !owner.serverUrl || owner.serverUrl.length > 2048) {
+    throw new Error('invalid_archive');
+  }
+  return JSON.stringify([owner.username.trim().toLowerCase(), trimUrl(owner.serverUrl)]);
+}
+
+/** Strict allowlist: nothing but the envelope fields is stored or echoed. */
+export function parseArchiveEnvelope(value: unknown): ArchiveEnvelope {
+  const v = value as ArchiveEnvelope | null;
+  const base64 = (s: unknown, bytes: (n: number) => boolean): s is string => {
+    if (typeof s !== 'string' || s.length > ARCHIVE_MAX_BYTES || !/^[A-Za-z0-9+/]+={0,2}$/.test(s) || s.length % 4) return false;
+    try { return bytes(atob(s).length); } catch { return false; }
+  };
+  if (!v || typeof v !== 'object' || v.version !== 1 || v.iterations !== ARCHIVE_ITERATIONS
+    || !base64(v.salt, n => n === 16) || !base64(v.iv, n => n === 12) || !base64(v.ciphertext, n => n > 16)) {
+    throw new Error('invalid_archive');
+  }
+  return { version: 1, iterations: ARCHIVE_ITERATIONS, salt: v.salt, iv: v.iv, ciphertext: v.ciphertext };
+}
+
+export function parseArchivedAccounts(value: unknown): ArchivedAccount[] {
+  if (!Array.isArray(value) || value.length < 1 || value.length > ARCHIVE_MAX_ACCOUNTS) throw new Error('invalid_archive');
+  return value.map((a: ArchivedAccount) => {
+    archiveIdentity(a);
+    if (typeof a.label !== 'string' || a.label.length > 320
+      || typeof a.avatarColor !== 'string' || !/^#[0-9a-f]{6}$/i.test(a.avatarColor)) throw new Error('invalid_archive');
+    // Rebuilt field by field, so nothing else (a password, say) survives a round trip.
+    return { username: a.username.trim(), serverUrl: trimUrl(a.serverUrl), label: a.label, avatarColor: a.avatarColor };
+  });
+}
+
+const encode = (bytes: Uint8Array) => btoa(String.fromCharCode(...bytes));
+const decode = (text: string) => Uint8Array.from(atob(text), c => c.charCodeAt(0));
+// The owner is sealed in: an envelope copied to another owner's slot will not open there.
+const additionalData = (owner: ArchiveOwner) => new TextEncoder().encode(`bulwark-account-archive:1:${archiveIdentity(owner)}`);
+
+async function deriveKey(password: string, salt: Uint8Array<ArrayBuffer>): Promise<CryptoKey> {
+  if (!globalThis.crypto?.subtle) throw new Error('https_required');
+  const material = await crypto.subtle.importKey('raw', new TextEncoder().encode(password), 'PBKDF2', false, ['deriveKey']);
+  return crypto.subtle.deriveKey({ name: 'PBKDF2', hash: 'SHA-256', salt, iterations: ARCHIVE_ITERATIONS },
+    material, { name: 'AES-GCM', length: 256 }, false, ['encrypt', 'decrypt']);
+}
+
+export async function encryptArchive(owner: ArchiveOwner, accounts: ArchivedAccount[], password: string): Promise<ArchiveEnvelope> {
+  if (password.length < ARCHIVE_MIN_PASSWORD || password.length > 1024) throw new Error('password_length');
+  const plaintext = new TextEncoder().encode(JSON.stringify({ accounts: parseArchivedAccounts(accounts) }));
+  const salt = crypto.getRandomValues(new Uint8Array(16));
+  const iv = crypto.getRandomValues(new Uint8Array(12));
+  const key = await deriveKey(password, salt);
+  const ciphertext = await crypto.subtle.encrypt({ name: 'AES-GCM', iv, additionalData: additionalData(owner) }, key, plaintext);
+  return parseArchiveEnvelope({ version: 1, iterations: ARCHIVE_ITERATIONS, salt: encode(salt), iv: encode(iv),
+    ciphertext: encode(new Uint8Array(ciphertext)) });
+}
+
+export async function decryptArchive(owner: ArchiveOwner, envelope: ArchiveEnvelope, password: string): Promise<ArchivedAccount[]> {
+  const clean = parseArchiveEnvelope(envelope);
+  if (password.length > 1024) throw new Error('unlock_failed');
+  const key = await deriveKey(password, decode(clean.salt));
+  let plaintext: ArrayBuffer;
+  try {
+    plaintext = await crypto.subtle.decrypt({ name: 'AES-GCM', iv: decode(clean.iv), additionalData: additionalData(owner) },
+      key, decode(clean.ciphertext));
+  } catch { throw new Error('unlock_failed'); }
+  return parseArchivedAccounts((JSON.parse(new TextDecoder().decode(plaintext)) as { accounts?: unknown }).accounts);
+}
diff --git a/lib/admin/types.ts b/lib/admin/types.ts
index 437712c37..807adbf5d 100644
--- a/lib/admin/types.ts
+++ b/lib/admin/types.ts
@@ -67,6 +67,8 @@ export interface FeatureGates {
   crossStarredViewEnabled: boolean;
   crossAllViewEnabled: boolean;
   unifiedCrossAccountEnabled: boolean;
+  /** Encrypted account list kept on the server, restorable on another device. */
+  accountArchiveEnabled: boolean;
 }
 
 export const DEFAULT_FEATURE_GATES: FeatureGates = {
@@ -94,6 +96,7 @@ export const DEFAULT_FEATURE_GATES: FeatureGates = {
   crossStarredViewEnabled: false,
   crossAllViewEnabled: false,
   unifiedCrossAccountEnabled: false,
+  accountArchiveEnabled: false,
 };
 
 export interface ThemePolicy {
diff --git a/lib/lite-config.ts b/lib/lite-config.ts
index 38d8dd4b4..d4a64501b 100644
--- a/lib/lite-config.ts
+++ b/lib/lite-config.ts
@@ -162,6 +162,8 @@ export function applyLitePolicy(raw: unknown): SettingsPolicy {
       pluginsEnabled: false,
       pluginsUploadEnabled: false,
       sidebarAppsEnabled: false,
+      // Kept by this app's server, which Lite does not have.
+      accountArchiveEnabled: false,
     },
     forceEnabledPlugins: [],
     approvedPlugins: [],
diff --git a/locales/ar/common.json b/locales/ar/common.json
index 6de5854db..6d7bd5973 100644
--- a/locales/ar/common.json
+++ b/locales/ar/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "اسحب لإعادة الترتيب",
         "add": "إضافة حساب"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "مشترك معي",
         "description": "الحسابات الجماعية والمشتركة التي يمكنك إدارتها. اختر واحدًا لتعديل مرشحاته، والرد التلقائي أثناء الغياب، والتقويمات، وجهات الاتصال.",
diff --git a/locales/ca/common.json b/locales/ca/common.json
index 01ab88b36..0c718ecdc 100644
--- a/locales/ca/common.json
+++ b/locales/ca/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Arrossegueu per reordenar",
         "add": "Afegeix un compte"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Compartit amb mi",
         "description": "Comptes de grup i compartits que podeu gestionar. Seleccioneu-ne un per editar-ne els filtres, la resposta automàtica, els calendaris i els contactes.",
diff --git a/locales/cs/common.json b/locales/cs/common.json
index 04c10f6e6..3a4ea0f8e 100644
--- a/locales/cs/common.json
+++ b/locales/cs/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Přetažením změňte pořadí",
         "add": "Přidat účet"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Sdíleno se mnou",
         "description": "Skupinové a sdílené účty, které můžete spravovat. Vyberte jeden pro úpravu jeho filtrů, odpovědi v nepřítomnosti, kalendářů a kontaktů.",
diff --git a/locales/da/common.json b/locales/da/common.json
index 0dd7e6e5a..c90f977b0 100644
--- a/locales/da/common.json
+++ b/locales/da/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Træk for at omarrangere",
         "add": "Tilføj konto"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Delt med mig",
         "description": "Gruppe- og delte konti, du kan administrere. Vælg en for at redigere dens filtre, autosvar ved fravær, kalendere og kontakter.",
diff --git a/locales/de/common.json b/locales/de/common.json
index d43a9bcd4..e6f9ed51c 100644
--- a/locales/de/common.json
+++ b/locales/de/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Zum Sortieren ziehen",
         "add": "Konto hinzufügen"
       },
+      "backup": {
+        "title": "Sicherung der Kontoliste",
+        "description": "Speichert die Liste der Konten in diesem Browser auf dem Server, verschlüsselt mit einem Passwort, das nur Sie kennen, und stellt sie auf einem anderen Gerät wieder her. Postfachpasswörter werden nicht gespeichert: Sie melden sich bei jedem wiederhergestellten Konto selbst an.",
+        "status_none": "Für {account} ist keine Liste gespeichert.",
+        "status_saved": "Für {account} ist eine Liste gespeichert.",
+        "save": "Liste speichern",
+        "restore": "Liste wiederherstellen",
+        "delete": "Gespeicherte Liste löschen",
+        "cancel": "Abbrechen",
+        "delete_confirm": "Die gespeicherte Kontoliste vom Server löschen?",
+        "password": "Sicherungspasswort",
+        "password_hint": "Mindestens 10 Zeichen. Es kann nicht wiederhergestellt werden: Wenn Sie es vergessen, speichern Sie die Liste erneut mit einem neuen.",
+        "restore_hint": "Das Passwort, das beim Speichern der Liste gewählt wurde.",
+        "confirm": "Passwort bestätigen",
+        "saved": "Liste gespeichert ({count, plural, one {# Konto} other {# Konten}}).",
+        "restored": "Hinzugefügte Konten: {added}. Bereits vorhandene, aktualisierte Konten: {updated}. Öffnen Sie jedes neue Konto in der Kontoliste, um sich anzumelden.",
+        "skipped": "{count, plural, one {# Konto wurde} other {# Konten wurden}} nicht hinzugefügt: Die Höchstzahl an Konten ist erreicht.",
+        "deleted": "Gespeicherte Liste gelöscht.",
+        "errors": {
+          "mismatch": "Die Passwörter stimmen nicht überein.",
+          "password_length": "Verwenden Sie mindestens 10 Zeichen.",
+          "unlock_failed": "Falsches Passwort, oder die Liste wurde für ein anderes Konto gespeichert.",
+          "owner_signin_required": "Melden Sie sich erneut bei diesem Konto an und versuchen Sie es dann noch einmal.",
+          "https_required": "Dafür ist eine sichere (HTTPS-)Verbindung nötig.",
+          "storage_failed": "Der Server konnte die Liste nicht lesen oder speichern. Versuchen Sie es später erneut."
+        }
+      },
       "shared_accounts": {
         "title": "Mit mir geteilt",
         "description": "Gruppen- und freigegebene Konten, die Sie verwalten können. Wählen Sie eines aus, um dessen Filter, Abwesenheitsnotiz, Kalender und Kontakte zu bearbeiten.",
diff --git a/locales/en/common.json b/locales/en/common.json
index 4721cb6cd..ca65a0f4d 100644
--- a/locales/en/common.json
+++ b/locales/en/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Drag to reorder",
         "add": "Add account"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Shared with me",
         "description": "Group and shared accounts you can manage. Select one to edit its filters, vacation responder, calendars, and contacts.",
diff --git a/locales/es/common.json b/locales/es/common.json
index 93e017212..8b0000c55 100644
--- a/locales/es/common.json
+++ b/locales/es/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Arrastra para reordenar",
         "add": "Añadir cuenta"
       },
+      "backup": {
+        "title": "Copia de la lista de cuentas",
+        "description": "Guarda en el servidor la lista de cuentas de este navegador, cifrada con una contraseña que solo tú conoces, y recupérala en otro dispositivo. Las contraseñas de los buzones no se guardan: inicias sesión tú en cada cuenta restaurada.",
+        "status_none": "No hay ninguna lista guardada para {account}.",
+        "status_saved": "Hay una lista guardada para {account}.",
+        "save": "Guardar lista",
+        "restore": "Restaurar lista",
+        "delete": "Eliminar lista guardada",
+        "cancel": "Cancelar",
+        "delete_confirm": "¿Eliminar del servidor la lista de cuentas guardada?",
+        "password": "Contraseña de la copia",
+        "password_hint": "Al menos 10 caracteres. No se puede recuperar: si la olvidas, vuelve a guardar la lista con una nueva.",
+        "restore_hint": "La contraseña elegida al guardar la lista.",
+        "confirm": "Confirmar contraseña",
+        "saved": "Lista guardada ({count, plural, one {# cuenta} other {# cuentas}}).",
+        "restored": "Cuentas añadidas: {added}. Cuentas ya presentes y actualizadas: {updated}. Abre cada cuenta nueva desde la lista de cuentas para iniciar sesión.",
+        "skipped": "{count, plural, one {# cuenta no se ha añadido} other {# cuentas no se han añadido}}: se ha alcanzado el límite de cuentas.",
+        "deleted": "Lista guardada eliminada.",
+        "errors": {
+          "mismatch": "Las contraseñas no coinciden.",
+          "password_length": "Usa al menos 10 caracteres.",
+          "unlock_failed": "Contraseña incorrecta, o la lista se guardó para otra cuenta.",
+          "owner_signin_required": "Vuelve a iniciar sesión en esta cuenta y reinténtalo.",
+          "https_required": "Se necesita una conexión segura (HTTPS).",
+          "storage_failed": "El servidor no ha podido leer ni guardar la lista. Inténtalo más tarde."
+        }
+      },
       "shared_accounts": {
         "title": "Compartido conmigo",
         "description": "Cuentas de grupo y compartidas que puedes gestionar. Selecciona una para editar sus filtros, respuesta de vacaciones, calendarios y contactos.",
diff --git a/locales/fa/common.json b/locales/fa/common.json
index 342711bd2..041f8deca 100644
--- a/locales/fa/common.json
+++ b/locales/fa/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "کشیدن",
         "add": "افزودن"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "اشتراکی با من",
         "description": "حساب‌های گروهی",
diff --git a/locales/fr/common.json b/locales/fr/common.json
index 7c8abdbd1..f9e44d769 100644
--- a/locales/fr/common.json
+++ b/locales/fr/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Faire glisser pour réorganiser",
         "add": "Ajouter un compte"
       },
+      "backup": {
+        "title": "Sauvegarde de la liste des comptes",
+        "description": "Conservez sur le serveur la liste des comptes de ce navigateur, chiffrée avec un mot de passe que vous seul connaissez, et retrouvez-la sur un autre appareil. Les mots de passe des boîtes ne sont pas enregistrés : vous vous connectez vous-même à chaque compte restauré.",
+        "status_none": "Aucune liste enregistrée pour {account}.",
+        "status_saved": "Une liste est enregistrée pour {account}.",
+        "save": "Enregistrer la liste",
+        "restore": "Restaurer la liste",
+        "delete": "Supprimer la liste enregistrée",
+        "cancel": "Annuler",
+        "delete_confirm": "Supprimer du serveur la liste de comptes enregistrée ?",
+        "password": "Mot de passe de la sauvegarde",
+        "password_hint": "Au moins 10 caractères. Il ne peut pas être récupéré : si vous l'oubliez, enregistrez à nouveau la liste avec un nouveau mot de passe.",
+        "restore_hint": "Le mot de passe choisi lors de l'enregistrement de la liste.",
+        "confirm": "Confirmer le mot de passe",
+        "saved": "Liste enregistrée ({count, plural, one {# compte} other {# comptes}}).",
+        "restored": "Comptes ajoutés : {added}. Comptes déjà présents et mis à jour : {updated}. Ouvrez chaque nouveau compte depuis la liste des comptes pour vous connecter.",
+        "skipped": "{count, plural, one {# compte n'a pas été ajouté} other {# comptes n'ont pas été ajoutés}} : la limite de comptes est atteinte.",
+        "deleted": "Liste enregistrée supprimée.",
+        "errors": {
+          "mismatch": "Les mots de passe ne correspondent pas.",
+          "password_length": "Utilisez au moins 10 caractères.",
+          "unlock_failed": "Mot de passe incorrect, ou la liste a été enregistrée pour un autre compte.",
+          "owner_signin_required": "Reconnectez-vous à ce compte, puis réessayez.",
+          "https_required": "Une connexion sécurisée (HTTPS) est nécessaire.",
+          "storage_failed": "Le serveur n'a pas pu lire ou enregistrer la liste. Réessayez plus tard."
+        }
+      },
       "shared_accounts": {
         "title": "Partagé avec moi",
         "description": "Comptes de groupe et partagés que vous pouvez gérer. Sélectionnez-en un pour modifier ses filtres, son répondeur d'absence, ses calendriers et ses contacts.",
diff --git a/locales/he/common.json b/locales/he/common.json
index af83e9046..feac99c98 100644
--- a/locales/he/common.json
+++ b/locales/he/common.json
@@ -1628,6 +1628,33 @@
         "drag_handle": "גרור לסדר",
         "add": "הוסף חשבון"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "משותף איתי",
         "description": "חשבונות קבוצתיים ומשותפים שאתה יכול לנהל. בחר אחד כדי לערוך את המסננים, המגיב לחופשה, לוחות השנה והאנשים שלו.",
diff --git a/locales/hu/common.json b/locales/hu/common.json
index 1850382fc..937bee3e1 100644
--- a/locales/hu/common.json
+++ b/locales/hu/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Húzd át a sorrend módosításához",
         "add": "Fiók hozzáadása"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Velem megosztva",
         "description": "Csoportos és megosztott fiókok, amelyeket kezelhet. Válasszon egyet a szűrői, távolléti válasza, naptárai és névjegyei szerkesztéséhez.",
diff --git a/locales/it/common.json b/locales/it/common.json
index c40767c5a..811da483c 100644
--- a/locales/it/common.json
+++ b/locales/it/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Trascina per riordinare",
         "add": "Aggiungi account"
       },
+      "backup": {
+        "title": "Backup dell'elenco account",
+        "description": "Conserva sul server l'elenco degli account di questo browser, cifrato con una password che conosci solo tu, e ripristinalo su un altro dispositivo. Le password delle caselle non vengono salvate: accedi tu a ogni account ripristinato.",
+        "status_none": "Nessun elenco salvato per {account}.",
+        "status_saved": "C'è un elenco salvato per {account}.",
+        "save": "Salva elenco",
+        "restore": "Ripristina elenco",
+        "delete": "Elimina elenco salvato",
+        "cancel": "Annulla",
+        "delete_confirm": "Eliminare dal server l'elenco account salvato?",
+        "password": "Password del backup",
+        "password_hint": "Almeno 10 caratteri. Non si può recuperare: se la dimentichi, salva di nuovo l'elenco con una nuova password.",
+        "restore_hint": "La password scelta quando l'elenco è stato salvato.",
+        "confirm": "Conferma password",
+        "saved": "Elenco salvato ({count, plural, one {# account} other {# account}}).",
+        "restored": "Account aggiunti: {added}. Account già presenti e aggiornati: {updated}. Apri ogni nuovo account dall'elenco account per accedere.",
+        "skipped": "{count, plural, one {# account non è stato aggiunto} other {# account non sono stati aggiunti}}: è stato raggiunto il limite di account.",
+        "deleted": "Elenco salvato eliminato.",
+        "errors": {
+          "mismatch": "Le password non coincidono.",
+          "password_length": "Usa almeno 10 caratteri.",
+          "unlock_failed": "Password errata, oppure l'elenco è stato salvato per un altro account.",
+          "owner_signin_required": "Accedi di nuovo a questo account, poi riprova.",
+          "https_required": "Serve una connessione sicura (HTTPS).",
+          "storage_failed": "Il server non è riuscito a leggere o salvare l'elenco. Riprova più tardi."
+        }
+      },
       "shared_accounts": {
         "title": "Condivisi con me",
         "description": "Account di gruppo e condivisi che puoi gestire. Selezionane uno per modificarne filtri, risponditore automatico, calendari e contatti.",
diff --git a/locales/ja/common.json b/locales/ja/common.json
index b5b3bb008..dbd3e4165 100644
--- a/locales/ja/common.json
+++ b/locales/ja/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "ドラッグして並べ替え",
         "add": "アカウントを追加"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "自分と共有",
         "description": "管理できるグループアカウントと共有アカウントです。1つ選択して、フィルター、不在応答、カレンダー、連絡先を編集します。",
diff --git a/locales/ko/common.json b/locales/ko/common.json
index c13698a8e..a550160e2 100644
--- a/locales/ko/common.json
+++ b/locales/ko/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "끌어서 순서 변경",
         "add": "계정 추가"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "나와 공유됨",
         "description": "관리할 수 있는 그룹 및 공유 계정입니다. 하나를 선택하여 필터, 부재 중 자동 응답, 캘린더, 연락처를 편집하세요.",
diff --git a/locales/lv/common.json b/locales/lv/common.json
index 0938cc474..4e98b1688 100644
--- a/locales/lv/common.json
+++ b/locales/lv/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Velciet, lai pārkārtotu",
         "add": "Pievienot kontu"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Kopīgots ar mani",
         "description": "Grupas un kopīgotie konti, kurus varat pārvaldīt. Atlasiet vienu, lai rediģētu tā filtrus, prombūtnes atbildētāju, kalendārus un kontaktus.",
diff --git a/locales/mn/common.json b/locales/mn/common.json
index 57cb87378..14e641ae2 100644
--- a/locales/mn/common.json
+++ b/locales/mn/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Дахин эрэмбэлэхийн тулд чирнэ үү",
         "add": "Бүртгэл нэмэх"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Надтай хуваалцсан",
         "description": "Бүлэг болон хуваалцсан акаунтуудыг удирдах боломжтой. Шүүлтүүр, амралтын хариулагч, хуанли, харилцагчдыг засахын тулд нэгийг нь сонгоно уу.",
diff --git a/locales/nb/common.json b/locales/nb/common.json
index d803d5ca7..fbb19d891 100644
--- a/locales/nb/common.json
+++ b/locales/nb/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Dra for å omorganisere",
         "add": "Legg til konto"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Delt med meg",
         "description": "Gruppekontoer og delte kontoer du kan administrere. Velg en konto for å redigere filtre, feriesvar, kalendere og kontakter.",
diff --git a/locales/nl/common.json b/locales/nl/common.json
index 00a6caf4d..4233ba43f 100644
--- a/locales/nl/common.json
+++ b/locales/nl/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Sleep om volgorde aan te passen",
         "add": "Account toevoegen"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Gedeeld met mij",
         "description": "Groeps- en gedeelde accounts die u kunt beheren. Selecteer er een om de filters, afwezigheidsassistent, agenda's en contacten te bewerken.",
diff --git a/locales/pl/common.json b/locales/pl/common.json
index 4da811ece..c964e618f 100644
--- a/locales/pl/common.json
+++ b/locales/pl/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Przeciągnij, aby zmienić kolejność",
         "add": "Dodaj konto"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Udostępnione mnie",
         "description": "Konta grupowe i udostępnione, którymi możesz zarządzać. Wybierz jedno, aby edytować jego filtry, odpowiedź wakacyjną, kalendarze i kontakty.",
diff --git a/locales/pt/common.json b/locales/pt/common.json
index cb0256721..57b2cd546 100644
--- a/locales/pt/common.json
+++ b/locales/pt/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Arraste para reordenar",
         "add": "Adicionar conta"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Compartilhado comigo",
         "description": "Contas de grupo e compartilhadas que você pode gerenciar. Selecione uma para editar seus filtros, resposta de ausência, calendários e contatos.",
diff --git a/locales/ro/common.json b/locales/ro/common.json
index fb85bab41..1215156b9 100644
--- a/locales/ro/common.json
+++ b/locales/ro/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Trageți pentru a reordona",
         "add": "Adăugare cont"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Partajat cu mine",
         "description": "Conturi de grup și conturi partajate pe care le puteți gestiona. Selectați unul pentru a-i edita filtrele, răspunsul automat de vacanță, calendarele și contactele.",
diff --git a/locales/ru/common.json b/locales/ru/common.json
index d6b37b4fc..32e171a5c 100644
--- a/locales/ru/common.json
+++ b/locales/ru/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Перетащите, чтобы изменить порядок",
         "add": "Добавить учётную запись"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Доступные мне",
         "description": "Групповые и общие учётные записи, которыми вы можете управлять. Выберите одну, чтобы изменить её фильтры, автоответчик, календари и контакты.",
diff --git a/locales/sk/common.json b/locales/sk/common.json
index 08eb583a0..e5438fac8 100644
--- a/locales/sk/common.json
+++ b/locales/sk/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "Presuňte na zmenu poradia",
         "add": "Pridať účet"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Zdieľané so mnou",
         "description": "Skupinové a zdieľané účty, ktoré môžete spravovať.",
diff --git a/locales/tr/common.json b/locales/tr/common.json
index 4f69291a0..4d558d13d 100644
--- a/locales/tr/common.json
+++ b/locales/tr/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Sıralamak için sürükleyin",
         "add": "Hesap ekle"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Benimle paylaşılanlar",
         "description": "Yönetebileceğiniz grup ve paylaşılan hesaplar. Filtrelerini, tatil yanıtlayıcısını, takvimlerini ve kişilerini düzenlemek için birini seçin.",
diff --git a/locales/uk/common.json b/locales/uk/common.json
index b53f0f5dd..e34525254 100644
--- a/locales/uk/common.json
+++ b/locales/uk/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "Перетягніть, щоб змінити порядок",
         "add": "Додати обліковий запис"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "Доступні мені",
         "description": "Групові та спільні облікові записи, якими ви можете керувати. Виберіть один, щоб змінити його фільтри, автовідповідач, календарі та контакти.",
diff --git a/locales/zh-TW/common.json b/locales/zh-TW/common.json
index d5318d90f..ac89d5b87 100644
--- a/locales/zh-TW/common.json
+++ b/locales/zh-TW/common.json
@@ -1666,6 +1666,33 @@
         "drag_handle": "拖曳以重新排序",
         "add": "新增帳號"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "與我共用",
         "description": "您可以管理的群組與共用帳號。選取一個帳號，即可編輯其篩選規則、休假自動回覆、行事曆與聯絡人。",
diff --git a/locales/zh/common.json b/locales/zh/common.json
index 68562edb8..8415e0bf6 100644
--- a/locales/zh/common.json
+++ b/locales/zh/common.json
@@ -1663,6 +1663,33 @@
         "drag_handle": "拖动以重新排序",
         "add": "添加账户"
       },
+      "backup": {
+        "title": "Account list backup",
+        "description": "Keep the list of accounts in this browser on the server, encrypted with a password only you know, and bring it back on another device. Mailbox passwords are not saved: you sign in to each restored account yourself.",
+        "status_none": "No list is saved for {account}.",
+        "status_saved": "A list is saved for {account}.",
+        "save": "Save list",
+        "restore": "Restore list",
+        "delete": "Delete saved list",
+        "cancel": "Cancel",
+        "delete_confirm": "Delete the saved account list from the server?",
+        "password": "Backup password",
+        "password_hint": "At least 10 characters. It cannot be recovered: if you forget it, save the list again with a new one.",
+        "restore_hint": "The password chosen when the list was saved.",
+        "confirm": "Confirm password",
+        "saved": "List saved ({count, plural, one {# account} other {# accounts}}).",
+        "restored": "Accounts added: {added}. Accounts already here and updated: {updated}. Open each new account from the account list to sign in.",
+        "skipped": "{count, plural, one {# account was} other {# accounts were}} not added: the account limit is reached.",
+        "deleted": "Saved list deleted.",
+        "errors": {
+          "mismatch": "The passwords do not match.",
+          "password_length": "Use at least 10 characters.",
+          "unlock_failed": "Wrong password, or the list was saved for another account.",
+          "owner_signin_required": "Sign in to this account again, then retry.",
+          "https_required": "This needs a secure (HTTPS) connection.",
+          "storage_failed": "The server could not read or store the list. Try again later."
+        }
+      },
       "shared_accounts": {
         "title": "与我共享",
         "description": "您可以管理的群组和共享账户。选择一个以编辑其筛选器、休假自动回复、日历和联系人。",
diff --git a/scripts/lite/lib.mjs b/scripts/lite/lib.mjs
index 6c5ed2dba..4340a1807 100644
--- a/scripts/lite/lib.mjs
+++ b/scripts/lite/lib.mjs
@@ -105,6 +105,8 @@ export const LITE_API_STRING_ALLOWLIST = [
   // Settings/policy - replaced by config.json / policy.json.
   "/api/config",
   "/api/admin/policy",
+  // lib/account-archive-client.ts - the feature is pinned off in Lite.
+  "/api/account-archive",
   // WOPI (#425) - use-wopi-status returns disabled in Lite.
   "/api/wopi/status",
   "/api/wopi/launch",
diff --git a/stores/__tests__/auth-store-archive-restore.test.ts b/stores/__tests__/auth-store-archive-restore.test.ts
new file mode 100644
index 000000000..50d429a84
--- /dev/null
+++ b/stores/__tests__/auth-store-archive-restore.test.ts
@@ -0,0 +1,97 @@
+import { beforeAll, beforeEach, expect, it, vi } from 'vitest';
+import { createConfig } from '@/lib/__tests__/fixtures/config';
+
+// Accounts restored from the account list backup carry no credentials. They
+// must stay listed until signed in, and opening one must lead to the sign-in
+// form instead of dropping it like an account whose session ran out.
+vi.mock('@/lib/jmap/client', () => {
+  class JMAPClient {
+    constructor(public serverUrl: string, public username: string, public password: string) {}
+    static withBearer() { throw new Error('not used'); }
+    async connect() {}
+    getSessionUsername() { return this.username; }
+    getUsername() { return this.username; }
+    async getIdentities() { return [{ id: 'a', email: this.username, name: this.username, mayDelete: false }]; }
+    getAuthHeader() { return 'Basic eA=='; }
+    onConnectionChange() {}
+    onRateLimit() {}
+    getRateLimitRemainingMs() { return 0; }
+    supportsContacts() { return false; }
+    supportsPrincipals() { return false; }
+    supportsVacationResponse() { return false; }
+    supportsCalendars() { return false; }
+    supportsSieve() { return false; }
+    disconnect() {}
+    getAccountId() { return 'acct'; }
+  }
+  class RateLimitError extends Error {}
+  return { JMAPClient, RateLimitError };
+});
+vi.mock('@/lib/stalwart/principal', () => ({ fetchPrincipalDisplayName: async () => null }));
+
+import * as nav from '@/lib/browser-navigation';
+import { useAuthStore } from '@/stores/auth-store';
+import { useAccountStore } from '@/stores/account-store';
+import { collectAccounts, restoreAccounts } from '@/lib/account-archive-client';
+
+const signedIn = {
+  id: 'bob@x.test@mail.x.test', label: 'Bob', serverUrl: 'https://mail.x.test', username: 'bob@x.test', authMode: 'basic' as const,
+  rememberMe: true, cookieSlot: 0, displayName: 'Bob', email: 'bob@x.test', isConnected: false, hasError: false,
+  lastLoginAt: 1, avatarColor: '#000000', isDefault: true,
+};
+const archived = [
+  { username: 'bob@x.test', serverUrl: 'https://mail.x.test', label: 'Bob at work', avatarColor: '#2563eb' },
+  { username: 'alice@x.test', serverUrl: 'https://mail.x.test', label: 'Alice', avatarColor: '#16a34a' },
+];
+const redirect = vi.fn();
+
+beforeAll(() => {
+  vi.stubGlobal('fetch', vi.fn(async (input: unknown) => {
+    const url = String(input);
+    if (url.includes('/api/auth/session')) {
+      return new Response(JSON.stringify({ serverUrl: signedIn.serverUrl, username: signedIn.username, password: 'x' }), { status: 200 });
+    }
+    if (url.includes('/api/config')) return new Response(JSON.stringify(createConfig()), { status: 200 });
+    return new Response('{}', { status: 200 });
+  }));
+  vi.spyOn(nav, 'replaceWindowLocation').mockImplementation(redirect);
+});
+
+beforeEach(() => {
+  redirect.mockClear();
+  useAccountStore.setState({ accounts: [signedIn] as never, activeAccountId: signedIn.id, defaultAccountId: signedIn.id });
+});
+
+it('adds missing accounts awaiting sign-in and relabels the ones already here', () => {
+  expect(collectAccounts()).toEqual([
+    { username: signedIn.username, serverUrl: signedIn.serverUrl, label: 'Bob', avatarColor: '#000000' },
+  ]);
+  expect(restoreAccounts(archived)).toEqual({ added: 1, updated: 1, skipped: 0 });
+  const [bob, alice] = useAccountStore.getState().accounts;
+  expect(bob).toMatchObject({ label: 'Bob at work', avatarColor: '#2563eb', isDefault: true });
+  expect(bob.awaitingSignIn).toBeUndefined();
+  expect(alice).toMatchObject({ id: 'alice@x.test@mail.x.test', label: 'Alice', avatarColor: '#16a34a', awaitingSignIn: true, rememberMe: false });
+});
+
+it('keeps a restored account through a reload and sends it to the sign-in form', async () => {
+  restoreAccounts(archived);
+  await useAuthStore.getState().checkAuth();
+  expect(useAuthStore.getState().activeAccountId).toBe(signedIn.id);
+  expect(useAccountStore.getState().accounts.map(a => a.id)).toEqual([signedIn.id, 'alice@x.test@mail.x.test']);
+
+  await useAuthStore.getState().switchAccount('alice@x.test@mail.x.test');
+  expect(redirect).toHaveBeenCalledWith(expect.stringMatching(/\/login\?mode=add-account&username=alice%40x\.test$/));
+  expect(useAccountStore.getState().accounts).toHaveLength(2);
+  expect(useAuthStore.getState().activeAccountId).toBe(signedIn.id);
+});
+
+it('stops waiting once the account is signed in', () => {
+  restoreAccounts(archived);
+  useAccountStore.getState().addAccount({
+    username: 'alice@x.test', serverUrl: 'https://mail.x.test', authMode: 'basic', rememberMe: true, label: 'alice',
+    displayName: 'alice', email: 'alice@x.test', lastLoginAt: 2, isConnected: true, hasError: false, isDefault: false,
+  });
+  const alice = useAccountStore.getState().getAccountById('alice@x.test@mail.x.test');
+  expect(alice).toMatchObject({ label: 'Alice', avatarColor: '#16a34a', isConnected: true });
+  expect(alice?.awaitingSignIn).toBeUndefined();
+});
diff --git a/stores/account-store.ts b/stores/account-store.ts
index 85af0991e..d43fe42c3 100644
--- a/stores/account-store.ts
+++ b/stores/account-store.ts
@@ -49,6 +49,11 @@ export interface AccountEntry {
   errorMessage?: string;
   /** Whether this is the default account (loaded on app start) */
   isDefault: boolean;
+  /**
+   * Brought back from the account list backup and not signed in on this
+   * device yet. Kept across reloads, and opening it leads to the sign-in form.
+   */
+  awaitingSignIn?: boolean;
 }
 
 interface AccountState {
@@ -93,6 +98,8 @@ export const useAccountStore = create<AccountState>()(
                     errorMessage: undefined,
                     lastLoginAt: entry.lastLoginAt,
                     authMode: entry.authMode,
+                    // Any sign-in ends the wait, whichever way it went.
+                    awaitingSignIn: entry.awaitingSignIn,
                   }
                 : a
             ),
diff --git a/stores/auth-store.ts b/stores/auth-store.ts
index 788cf7b76..eb8076bfe 100644
--- a/stores/auth-store.ts
+++ b/stores/auth-store.ts
@@ -2279,6 +2279,12 @@ export const useAuthStore = create<AuthState>()(
         const accountStore = useAccountStore.getState();
         const targetAccount = accountStore.getAccountById(accountId);
         if (!targetAccount) return;
+        // Restored from the account list backup and never signed in here:
+        // there is no session to resume, so ask for the password instead.
+        if (targetAccount.awaitingSignIn && !clients.has(accountId)) {
+          replaceWindowLocation(`${getLocaleLoginPath()}?mode=add-account&username=${encodeURIComponent(targetAccount.username)}`);
+          return;
+        }
 
         // A switch between two already-connected accounts is done seamlessly:
         // the current account's client and mail stay on screen while we verify
@@ -2562,6 +2568,8 @@ export const useAuthStore = create<AuthState>()(
           // overlaps the connect instead of running after it.
           const restoreAccount = async (account: (typeof accounts)[number]) => {
             if (clients.has(account.id)) return; // Already connected
+            // Restored from the account list backup: listed until signed in.
+            if (account.awaitingSignIn) return;
 
             // A password or access token login without rememberMe leaves
             // nothing to restore - the user logged in without persisting

From 388c12e01bd837206e662474708d71720d9206ef Mon Sep 17 00:00:00 2001
From: Sienna Meridian Satterwhite <sienna@r3t.io>
Date: Fri, 9 Oct 2026 15:56:25 +0100
Subject: [PATCH 17/23] feat(plugins): expose event uid + attendees and fire
 the form-save hook
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Plugins rendering in calendar-event-actions could never see the event's
uid or participants, so a meeting plugin minted a fresh room on every
click and could never propagate attendee or time changes; and of the
declared calendar hooks, none ever fired — the form-save bus existed but
had no emit site anywhere.

- calendar-event-actions eventData gains uid (undefined for new drafts)
  and attendees (email list), so plugins can key meetings off the event
  and fan out to participants.
- onCalendarEventFormSave now fires in handleSave as a transform:
  handlers receive the accumulated patch plus the form view and may
  return a patch (currently { virtualLocation }) merged into the saved
  event — a meeting plugin refreshes its link in the same save that
  sends scheduling messages, so attendees always get the current URL.
- Both buses are typed; contract tests cover the patch flow.

Testing: vitest plugin-hooks suite (41 passing), tsc clean, eslint clean
on touched files.
---
 components/calendar/event-modal.tsx | 45 +++++++++++++++++++++++++-
 lib/__tests__/plugin-hooks.test.ts  | 49 +++++++++++++++++++++++++++++
 lib/plugin-hooks.ts                 | 26 +++++++++++++--
 lib/plugin-types.ts                 |  4 +++
 4 files changed, 121 insertions(+), 3 deletions(-)

diff --git a/components/calendar/event-modal.tsx b/components/calendar/event-modal.tsx
index e2eccfe67..53b333280 100644
--- a/components/calendar/event-modal.tsx
+++ b/components/calendar/event-modal.tsx
@@ -32,7 +32,11 @@ import { buildDuplicateEventData } from "@/lib/calendar-duplicate";
 import { useFormatEventDate } from "@/hooks/use-format-event-date";
 import { useIsPaneScoped } from "@/hooks/use-pane-context";
 import { useContactNameResolver } from "@/hooks/use-contact-name-resolver";
-import { calendarHooks } from "@/lib/plugin-hooks";
+import {
+  calendarFormHooks,
+  calendarHooks,
+  type CalendarEventFormSavePatch,
+} from "@/lib/plugin-hooks";
 import type { ConflictWarning } from "@/lib/plugin-types";
 
 export interface PendingEventPreview {
@@ -641,6 +645,43 @@ export function EventModal({
       data.organizerCalendarAddress = null;
     }
 
+    // Plugin form-save hook: a handler may refresh form-derived values
+    // (currently the virtual-location link) in the same save that sends
+    // scheduling messages, so invites carry what plugins set here rather
+    // than a stale value from before the save.
+    const pluginPatch = await calendarFormHooks.onCalendarEventFormSave.transform<
+      CalendarEventFormSavePatch
+    >(
+      {},
+      {
+        title: trimmedTitle,
+        description: trimmedDescription,
+        start: startStr,
+        end: allDay ? `${endDate}T23:59:59` : `${endDate}T${endTime}:00`,
+        isAllDay: allDay,
+        location,
+        virtualLocation,
+        calendarId,
+        uid: data.uid ?? event?.uid,
+        attendees: effectiveAttendees.map((a) => a.email),
+      },
+    );
+    if (pluginPatch && typeof pluginPatch.virtualLocation === "string") {
+      if (pluginPatch.virtualLocation.trim()) {
+        data.virtualLocations = {
+          vl1: {
+            "@type": "VirtualLocation",
+            name: null,
+            description: null,
+            uri: pluginPatch.virtualLocation.trim(),
+            features: null,
+          },
+        };
+      } else {
+        data.virtualLocations = null;
+      }
+    }
+
     const shouldSendScheduling = effectiveAttendees.length > 0 && sendInvitations;
     setIsSaving(true);
     try {
@@ -1106,6 +1147,8 @@ export function EventModal({
                   location,
                   virtualLocation,
                   calendarId,
+                  uid: event?.uid,
+                  attendees: attendees.map((a) => a.email),
                 },
                 setVirtualLocation,
               }}
diff --git a/lib/__tests__/plugin-hooks.test.ts b/lib/__tests__/plugin-hooks.test.ts
index 139dab290..ee5848c3e 100644
--- a/lib/__tests__/plugin-hooks.test.ts
+++ b/lib/__tests__/plugin-hooks.test.ts
@@ -1,5 +1,6 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
 import { HookBus, pluginErrorTracker, removeAllPluginHooks, clearAllHooks, emailHooks, calendarHooks, isExternalAttachmentResult } from '../plugin-hooks';
+import type { CalendarEventFormView } from '../plugin-types';
 
 beforeEach(() => {
   pluginErrorTracker.resetAll();
@@ -294,6 +295,54 @@ describe('Hook domain instances', () => {
     expect(calendarHooks.onBeforeEventCreate).toBeInstanceOf(HookBus);
     expect(calendarHooks.onEventRsvp).toBeInstanceOf(HookBus);
   });
+
+  it('onCalendarEventFormSave pipes a returned patch through transform with the form view', async () => {
+    const { calendarFormHooks } = await import('../plugin-hooks');
+    const views: CalendarEventFormView[] = [];
+    const disposable = calendarFormHooks.onCalendarEventFormSave.register(
+      'test-p',
+      async (_patch, view) => {
+        views.push(view);
+        return { virtualLocation: 'https://meet.example.com/rooms/x?role=host' };
+      },
+    );
+
+    const patch = await calendarFormHooks.onCalendarEventFormSave.transform(
+      {},
+      {
+        title: 'Team Sync',
+        description: '',
+        start: '2026-10-09T10:00:00',
+        end: '2026-10-09T11:00:00',
+        isAllDay: false,
+        location: '',
+        virtualLocation: '',
+        calendarId: 'cal-1',
+        uid: 'uid-1',
+        attendees: ['a@sunbeam.pt'],
+      },
+    );
+
+    expect(patch).toEqual({ virtualLocation: 'https://meet.example.com/rooms/x?role=host' });
+    expect(views[0]).toMatchObject({ title: 'Team Sync', uid: 'uid-1', attendees: ['a@sunbeam.pt'] });
+    disposable.dispose();
+  });
+
+  it('onCalendarEventFormSave keeps the form unchanged when handlers return undefined', async () => {
+    const { calendarFormHooks } = await import('../plugin-hooks');
+    const disposable = calendarFormHooks.onCalendarEventFormSave.register('test-p', async () => undefined);
+
+    const patch = await calendarFormHooks.onCalendarEventFormSave.transform(
+      { virtualLocation: 'keep-me' },
+      {
+        title: 'T', description: '', start: '', end: '', isAllDay: false,
+        location: '', virtualLocation: '', calendarId: 'cal-1', attendees: [],
+      },
+    );
+
+    expect(patch).toEqual({ virtualLocation: 'keep-me' });
+    disposable.dispose();
+  });
 });
 
 describe('removeAllPluginHooks', () => {
diff --git a/lib/plugin-hooks.ts b/lib/plugin-hooks.ts
index fcb76f605..afbd022fe 100644
--- a/lib/plugin-hooks.ts
+++ b/lib/plugin-hooks.ts
@@ -1,6 +1,6 @@
 // Plugin Hook Bus - event bus system for plugin lifecycle hooks
 
-import type { Disposable } from './plugin-types';
+import type { CalendarEventFormView, Disposable } from './plugin-types';
 
 // ─── Error Tracker (Circuit Breaker) ─────────────────────────
 
@@ -369,9 +369,31 @@ export const calendarHooks = {
 };
 
 // §7.2b Calendar Form Hooks (UI integration)
+
+/** What onCalendarEventFormSave handlers may set on the event being saved. */
+export interface CalendarEventFormSavePatch {
+  virtualLocation?: string;
+}
+
 export const calendarFormHooks = {
   onCalendarEventFormOpen: new HookBus(),
-  onCalendarEventFormSave: new HookBus(),
+  /**
+   * Fires while the event form is being saved. Handlers receive the patch
+   * accumulated so far and the form view (including the event uid and
+   * attendee emails), and may return a partial patch that the form merges
+   * into the saved event, so a meeting plugin can refresh its link in the
+   * same save that sends scheduling messages and attendees receive the
+   * current URL. Returning undefined leaves the patch unchanged.
+   */
+  onCalendarEventFormSave: new HookBus<
+    (
+      patch: CalendarEventFormSavePatch,
+      view: CalendarEventFormView,
+    ) =>
+      | Promise<CalendarEventFormSavePatch | undefined>
+      | CalendarEventFormSavePatch
+      | undefined
+  >(),
 };
 
 // §7.3 Contact Hooks
diff --git a/lib/plugin-types.ts b/lib/plugin-types.ts
index fee38be06..f46a40f0e 100644
--- a/lib/plugin-types.ts
+++ b/lib/plugin-types.ts
@@ -379,6 +379,10 @@ export interface CalendarEventFormView {
   location: string;
   virtualLocation: string;
   calendarId: string;
+  /** JMAP uid of the event being edited; undefined while composing a new one. */
+  uid?: string;
+  /** Attendee email addresses currently on the form. */
+  attendees: string[];
 }
 
 export interface KeyboardShortcut {

From c46da336049004e3d697c925b95509eaacc22915 Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Sat, 10 Oct 2026 19:23:27 +0200
Subject: [PATCH 18/23] fix: block a second save while a plugin's form-save
 hook runs #1202

The hook ran before the modal entered its saving state, so Save and
Ctrl+Enter stayed live while a plugin handler was busy. Each extra press
created another event with a fresh uid and sent another invitation.

- mark the modal as saving before the hook runs
- pass uid and attendees to the conflict-check view too
- don't send a null meeting link when creating an event
---
 .../event-modal-form-save-hook.test.tsx       | 53 ++++++++++++
 components/calendar/event-modal.tsx           | 84 +++++++++++--------
 2 files changed, 101 insertions(+), 36 deletions(-)
 create mode 100644 components/calendar/__tests__/event-modal-form-save-hook.test.tsx

diff --git a/components/calendar/__tests__/event-modal-form-save-hook.test.tsx b/components/calendar/__tests__/event-modal-form-save-hook.test.tsx
new file mode 100644
index 000000000..a92453de0
--- /dev/null
+++ b/components/calendar/__tests__/event-modal-form-save-hook.test.tsx
@@ -0,0 +1,53 @@
+import { render, screen, fireEvent, waitFor, act } from '@testing-library/react';
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { EventModal } from '../event-modal';
+import { calendarFormHooks, removeAllPluginHooks } from '@/lib/plugin-hooks';
+import type { Calendar } from '@/lib/jmap/types';
+
+// The form-save hook runs before the event is saved. A plugin handler can take
+// a while (minting a meeting room), and the save must count as in flight for
+// that whole time, or a second click creates the new event twice.
+
+const calendars = [
+  { id: 'cal-1', name: 'Work', isDefault: true, myRights: { mayWriteAll: true, mayWriteOwn: true } },
+] as unknown as Calendar[];
+
+afterEach(() => {
+  removeAllPluginHooks('test-plugin');
+});
+
+describe('EventModal form-save hook', () => {
+  it('saves once when Save is pressed again while a plugin handler is running', async () => {
+    let release!: () => void;
+    const gate = new Promise<void>((resolve) => { release = resolve; });
+    calendarFormHooks.onCalendarEventFormSave.register('test-plugin', async () => {
+      await gate;
+      return { virtualLocation: 'https://meet.example.com/room-1' };
+    });
+    const onSave = vi.fn().mockResolvedValue(undefined);
+
+    render(
+      <EventModal
+        calendars={calendars}
+        defaultDate={new Date('2026-10-12T10:00:00')}
+        defaultCalendarId="cal-1"
+        onSave={onSave}
+        onClose={vi.fn()}
+      />,
+    );
+
+    fireEvent.change(screen.getByPlaceholderText('form.title'), { target: { value: 'Sync' } });
+    const save = screen.getByText('form.save');
+    fireEvent.click(save);
+    fireEvent.click(save);
+    fireEvent.keyDown(window, { key: 'Enter', ctrlKey: true });
+
+    await act(async () => { release(); });
+    await waitFor(() => expect(onSave).toHaveBeenCalledTimes(1));
+    // Give a stray second save the chance to show up.
+    await act(async () => { await new Promise((r) => setTimeout(r, 20)); });
+    expect(onSave).toHaveBeenCalledTimes(1);
+    const data = onSave.mock.calls[0][0];
+    expect(Object.values(data.virtualLocations)[0]).toMatchObject({ uri: 'https://meet.example.com/room-1' });
+  });
+});
diff --git a/components/calendar/event-modal.tsx b/components/calendar/event-modal.tsx
index 53b333280..a8d65cf64 100644
--- a/components/calendar/event-modal.tsx
+++ b/components/calendar/event-modal.tsx
@@ -410,6 +410,8 @@ export function EventModal({
   }, []);
   const [showDeleteConfirm, setShowDeleteConfirm] = useState(false);
   const [isSaving, setIsSaving] = useState(false);
+  // Set synchronously, so a second save in the same tick is refused too.
+  const savingRef = useRef(false);
 
   const [attendees, setAttendees] = useState<{ name: string; email: string }[]>(() => {
     if (!event?.participants) return [];
@@ -464,12 +466,14 @@ export function EventModal({
           location,
           virtualLocation,
           calendarId,
+          uid: event?.uid,
+          attendees: attendees.map((a) => a.email),
         },
       });
       if (!cancelled) setPluginConflictWarnings(warnings);
     }, 250);
     return () => { cancelled = true; clearTimeout(t); };
-  }, [title, description, startDate, startTime, endDate, endTime, allDay, location, virtualLocation, calendarId]);
+  }, [title, description, startDate, startTime, endDate, endTime, allDay, location, virtualLocation, calendarId, event?.uid, attendees]);
 
   // Report live preview to parent for grid outline
   useEffect(() => {
@@ -498,7 +502,7 @@ export function EventModal({
 
   const handleSave = useCallback(async () => {
     const trimmedTitle = title.trim();
-    if (!trimmedTitle || isSaving) return;
+    if (!trimmedTitle || isSaving || savingRef.current) return;
     if (trimmedTitle.length > 500 || description.trim().length > 10000 || location.trim().length > 500) {
       // This guard returned silently, so a rejected save was indistinguishable from a dead
       // button. The fields also enforce their limits via maxLength, so this is a backstop —
@@ -649,44 +653,52 @@ export function EventModal({
     // (currently the virtual-location link) in the same save that sends
     // scheduling messages, so invites carry what plugins set here rather
     // than a stale value from before the save.
-    const pluginPatch = await calendarFormHooks.onCalendarEventFormSave.transform<
-      CalendarEventFormSavePatch
-    >(
-      {},
-      {
-        title: trimmedTitle,
-        description: trimmedDescription,
-        start: startStr,
-        end: allDay ? `${endDate}T23:59:59` : `${endDate}T${endTime}:00`,
-        isAllDay: allDay,
-        location,
-        virtualLocation,
-        calendarId,
-        uid: data.uid ?? event?.uid,
-        attendees: effectiveAttendees.map((a) => a.email),
-      },
-    );
-    if (pluginPatch && typeof pluginPatch.virtualLocation === "string") {
-      if (pluginPatch.virtualLocation.trim()) {
-        data.virtualLocations = {
-          vl1: {
-            "@type": "VirtualLocation",
-            name: null,
-            description: null,
-            uri: pluginPatch.virtualLocation.trim(),
-            features: null,
-          },
-        };
-      } else {
-        data.virtualLocations = null;
-      }
-    }
-
-    const shouldSendScheduling = effectiveAttendees.length > 0 && sendInvitations;
+    // The handlers can take seconds (a plugin minting a meeting room), so the
+    // save counts as in flight from here: a second click or Ctrl+Enter must
+    // not start another save, which for a new event would create a second
+    // copy (fresh uid) and send its invitations twice.
+    savingRef.current = true;
     setIsSaving(true);
     try {
+      const pluginPatch = await calendarFormHooks.onCalendarEventFormSave.transform<
+        CalendarEventFormSavePatch
+      >(
+        {},
+        {
+          title: trimmedTitle,
+          description: trimmedDescription,
+          start: startStr,
+          end: allDay ? `${endDate}T23:59:59` : `${endDate}T${endTime}:00`,
+          isAllDay: allDay,
+          location,
+          virtualLocation,
+          calendarId,
+          uid: data.uid ?? event?.uid,
+          attendees: effectiveAttendees.map((a) => a.email),
+        },
+      );
+      if (pluginPatch && typeof pluginPatch.virtualLocation === "string") {
+        if (pluginPatch.virtualLocation.trim()) {
+          data.virtualLocations = {
+            vl1: {
+              "@type": "VirtualLocation",
+              name: null,
+              description: null,
+              uri: pluginPatch.virtualLocation.trim(),
+              features: null,
+            },
+          };
+        } else if (event) {
+          data.virtualLocations = null;
+        } else {
+          delete data.virtualLocations;
+        }
+      }
+
+      const shouldSendScheduling = effectiveAttendees.length > 0 && sendInvitations;
       await onSave(data, shouldSendScheduling);
     } finally {
+      savingRef.current = false;
       setIsSaving(false);
     }
   }, [title, description, location, virtualLocation, startDate, startTime, endDate, endTime, allDay, calendarId, recurrence, customRule, alertRows, attendees, sendInvitations, currentUserEmails, existingParticipants, resolveContactName, event, onSave, isSaving, t]);

From 5f749fea63ebc87114dff22ad72e3f570eec7eea Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Sat, 10 Oct 2026 19:23:59 +0200
Subject: [PATCH 19/23] fix: sign out of one account without dropping the
 others #1201

Logout switched to the first account in the list. After a restore that
is often an account still waiting for sign-in, which has no client, so
logout took the full sign-out path and dropped every account. It now
switches to the first account that is connected.

Boot also counted waiting accounts when deciding whether any account
could be restored, so a reload with only waiting accounts left showed a
connection error instead of the login page.
---
 .../auth-store-archive-restore.test.ts        | 24 +++++++++++++++++++
 stores/auth-store.ts                          | 17 ++++++++++---
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/stores/__tests__/auth-store-archive-restore.test.ts b/stores/__tests__/auth-store-archive-restore.test.ts
index 50d429a84..47f51b689 100644
--- a/stores/__tests__/auth-store-archive-restore.test.ts
+++ b/stores/__tests__/auth-store-archive-restore.test.ts
@@ -95,3 +95,27 @@ it('stops waiting once the account is signed in', () => {
   expect(alice).toMatchObject({ label: 'Alice', avatarColor: '#16a34a', isConnected: true });
   expect(alice?.awaitingSignIn).toBeUndefined();
 });
+
+it('signs out to an account that is signed in, not to one awaiting sign-in', async () => {
+  restoreAccounts(archived);
+  useAccountStore.setState((s) => ({
+    accounts: [...s.accounts, { ...signedIn, id: 'carol@x.test@mail.x.test', username: 'carol@x.test', email: 'carol@x.test', label: 'Carol', cookieSlot: 2, isDefault: false }] as never,
+  }));
+  await useAuthStore.getState().checkAuth();
+  // Wait for the background restore of the other remembered account.
+  await vi.waitFor(() => expect(useAccountStore.getState().getAccountById('carol@x.test@mail.x.test')?.isConnected).toBe(true));
+
+  await useAuthStore.getState().logout();
+  expect(useAuthStore.getState().activeAccountId).toBe('carol@x.test@mail.x.test');
+  expect(useAuthStore.getState().isAuthenticated).toBe(true);
+  expect(useAccountStore.getState().accounts.map(a => a.id)).toEqual(['alice@x.test@mail.x.test', 'carol@x.test@mail.x.test']);
+});
+
+it('treats a browser left with only accounts awaiting sign-in as signed out, not as a connection failure', async () => {
+  useAccountStore.setState({ accounts: [{ ...signedIn, rememberMe: false }] as never });
+  restoreAccounts(archived.slice(1));
+  await useAuthStore.getState().checkAuth();
+  expect(useAuthStore.getState().isAuthenticated).toBe(false);
+  expect(useAuthStore.getState().error).not.toBe('connection_failed');
+  expect(useAccountStore.getState().accounts.map(a => a.id)).toEqual(['alice@x.test@mail.x.test']);
+});
diff --git a/stores/auth-store.ts b/stores/auth-store.ts
index eb8076bfe..5a79f6ba4 100644
--- a/stores/auth-store.ts
+++ b/stores/auth-store.ts
@@ -2112,7 +2112,13 @@ export const useAuthStore = create<AuthState>()(
 
         // Check if there are remaining accounts to switch to. Read the store
         // afresh: `accountStore` is the state from before removeAccount().
-        const nextAccount = wasDemoMode ? undefined : useAccountStore.getState().accounts[0];
+        // Prefer an account that is signed in here: one restored from the
+        // account list backup (or otherwise not connected) has no client, and
+        // picking it signs out every account left.
+        const remainingAccounts = useAccountStore.getState().accounts;
+        const nextAccount = wasDemoMode
+          ? undefined
+          : remainingAccounts.find((a) => clients.has(a.id)) ?? remainingAccounts[0];
         const droppedAccounts: AccountEntry[] = [];
 
         if (nextAccount) {
@@ -2762,8 +2768,13 @@ export const useAuthStore = create<AuthState>()(
             }
           }
 
-          // No accounts could be restored
-          if (accounts.some((account) => accountStore.getAccountById(account.id))) {
+          // No accounts could be restored. Accounts restored from the account
+          // list backup were never signed in here, so they say nothing about
+          // the connection.
+          if (accounts.some((account) => {
+            const entry = accountStore.getAccountById(account.id);
+            return entry && !entry.awaitingSignIn;
+          })) {
             set({
               isAuthenticated: false,
               isLoading: false,

From 53c1bd29a1c5f8b6f1286131997838fdf9ada513 Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Sat, 10 Oct 2026 19:24:10 +0200
Subject: [PATCH 20/23] fix: show a toast when a Mountain View toolbar action
 fails #1168

The toolbar's run() had only try/finally, so a failed archive or tag
write rejected silently. Delete, move and archive now go through
runBatchEmailAction with the same messages as the default list, and
tag, read and spam actions show their success and error toasts.

The top bar also starts update polling. It replaces the rail, which
used to start it, so the update dot on the admin icon never showed.
---
 .../email/__tests__/mv-list-toolbar.test.tsx  | 48 ++++++++++++++++
 components/email/mv-list-toolbar.tsx          | 55 ++++++++++++++++---
 components/layout/mv-top-bar.tsx              |  4 ++
 3 files changed, 100 insertions(+), 7 deletions(-)

diff --git a/components/email/__tests__/mv-list-toolbar.test.tsx b/components/email/__tests__/mv-list-toolbar.test.tsx
index 22a6006ef..2c715820c 100644
--- a/components/email/__tests__/mv-list-toolbar.test.tsx
+++ b/components/email/__tests__/mv-list-toolbar.test.tsx
@@ -156,3 +156,51 @@ describe('MvListToolbar overflow menu', () => {
     expect(onEmptyFolder).toHaveBeenCalledOnce();
   });
 });
+
+const { toast } = await import('@/stores/toast-store');
+const { ArchiveMailboxNotFoundError } = await import('@/stores/email-store');
+
+describe('MvListToolbar failure feedback', () => {
+  beforeEach(() => {
+    vi.restoreAllMocks();
+    useAuthStore.setState({ client: {} as never } as never);
+    useSettingsStore.setState({
+      emailKeywords: [{ id: 'work', label: 'Work', color: 'blue' }],
+      nestedTags: false,
+    } as never);
+    useEmailStore.setState({
+      emails: [message('a'), message('b')],
+      mailboxes,
+      selectedMailbox: 'inbox',
+      selectedEmailIds: new Set(['a', 'b']),
+      isUnifiedView: false,
+      unifiedRole: null,
+      error: null,
+    } as never);
+  });
+
+  it('says why archiving failed instead of failing silently', async () => {
+    const error = vi.spyOn(toast, 'error').mockImplementation(() => '' as never);
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    useEmailStore.setState({
+      batchArchive: vi.fn().mockRejectedValue(new ArchiveMailboxNotFoundError()),
+    } as never);
+    render(<MvListToolbar loadedCount={2} onRefresh={() => {}} />);
+
+    fireEvent.click(screen.getByLabelText('archive'));
+
+    await waitFor(() => expect(error).toHaveBeenCalledWith('error_archiving', 'archive_mailbox_not_found'));
+  });
+
+  it('reports a tag write that the server refused', async () => {
+    const error = vi.spyOn(toast, 'error').mockImplementation(() => '' as never);
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    useEmailStore.setState({ batchSetTag: vi.fn().mockRejectedValue(new Error('forbidden')) } as never);
+    render(<MvListToolbar loadedCount={2} onRefresh={() => {}} />);
+
+    fireEvent.click(screen.getByLabelText('tag'));
+    fireEvent.click(screen.getByText('Work'));
+
+    await waitFor(() => expect(error).toHaveBeenCalledWith('error_updating'));
+  });
+});
diff --git a/components/email/mv-list-toolbar.tsx b/components/email/mv-list-toolbar.tsx
index 1631c972d..b26b865ec 100644
--- a/components/email/mv-list-toolbar.tsx
+++ b/components/email/mv-list-toolbar.tsx
@@ -19,7 +19,9 @@ import {
 } from "@/components/icons";
 import { useTranslations } from "next-intl";
 import { useAuthStore } from "@/stores/auth-store";
-import { useEmailStore } from "@/stores/email-store";
+import { useEmailStore, ArchiveMailboxNotFoundError } from "@/stores/email-store";
+import { runBatchEmailAction } from "@/lib/email-action-toast";
+import { toast } from "@/stores/toast-store";
 import { useConfirmDialog } from "@/hooks/use-confirm-dialog";
 import { useMenuNavigation } from "@/hooks/use-menu-navigation";
 import { ConfirmDialog } from "@/components/ui/confirm-dialog";
@@ -102,6 +104,8 @@ export function MvListToolbar({
   const tSidebar = useTranslations("sidebar");
   const tCommon = useTranslations("common");
   const tViewer = useTranslations("email_viewer");
+  const tNotifications = useTranslations("notifications");
+  const tSpam = useTranslations("email_viewer.spam");
 
   const client = useAuthStore((s) => s.client);
   const {
@@ -190,11 +194,26 @@ export function MvListToolbar({
   // Marking your own drafts or sent mail as spam is meaningless.
   const spamApplicable = !["sent", "drafts", "scheduled"].includes(currentRole ?? "");
 
-  const run = async (action: () => Promise<void>) => {
+  // Every action reports its outcome the way the default toolbar does: a
+  // rejected promise or a store error turns into an error toast instead of
+  // an unhandled rejection with nothing on screen.
+  const run = async (
+    action: () => Promise<void>,
+    messages?: Parameters<typeof runBatchEmailAction>[1],
+  ) => {
     if (!client || isProcessing) return;
     setIsProcessing(true);
     try {
-      await action();
+      if (messages) {
+        await runBatchEmailAction(action, messages);
+      } else {
+        try {
+          await action();
+        } catch (error) {
+          console.error("Mountain View toolbar action failed:", error);
+          toast.error(tNotifications("error_updating"));
+        }
+      }
     } finally {
       setTimeout(() => setIsProcessing(false), 400);
     }
@@ -222,7 +241,10 @@ export function MvListToolbar({
         variant: "destructive",
       });
       if (!confirmed) return;
-      await batchDelete(client, isInTrash);
+      await runBatchEmailAction(() => batchDelete(client, isInTrash), {
+        success: tNotifications("emails_deleted", { count: selectionCount }),
+        error: tNotifications("error_deleting"),
+      });
     });
 
   const selectedEmails = emails.filter((email) => selectedEmailIds.has(email.id));
@@ -277,8 +299,12 @@ export function MvListToolbar({
 
   const handleMove = (mailboxId: string) => {
     setMoveOpen(false);
+    const count = selectionCount;
     void run(async () => {
       if (client) await batchMoveToMailbox(client, mailboxId);
+    }, {
+      success: tNotifications("emails_moved", { count }),
+      error: tNotifications("move_failed"),
     });
   };
 
@@ -295,8 +321,17 @@ export function MvListToolbar({
     run(async () => {
       if (!client) return;
       const ids = Array.from(selectedEmailIds);
-      if (isInJunk) await batchUndoSpam(client, ids);
-      else await batchMarkAsSpam(client, ids);
+      try {
+        if (isInJunk) {
+          await batchUndoSpam(client, ids);
+          toast.success(tSpam("toast_not_spam_batch", { count: ids.length }));
+        } else {
+          await batchMarkAsSpam(client, ids);
+          toast.success(tSpam("toast_batch", { count: ids.length }));
+        }
+      } catch {
+        toast.error(isInJunk ? tSpam("error_not_spam") : tSpam("error"));
+      }
     });
 
   return (
@@ -414,7 +449,13 @@ export function MvListToolbar({
           <ToolbarButton
             icon={Archive}
             label={tActions("archive")}
-            onClick={() => run(async () => { if (client) await batchArchive(client); })}
+            onClick={() => run(async () => { if (client) await batchArchive(client); }, {
+              success: tNotifications("emails_archived", { count: selectionCount }),
+              error: tNotifications("error_archiving"),
+              describeError: (error) => error instanceof ArchiveMailboxNotFoundError
+                ? tViewer("archive_mailbox_not_found")
+                : undefined,
+            })}
             disabled={isProcessing}
             busy={isProcessing}
           />
diff --git a/components/layout/mv-top-bar.tsx b/components/layout/mv-top-bar.tsx
index ec5cc51d5..383ac5e74 100644
--- a/components/layout/mv-top-bar.tsx
+++ b/components/layout/mv-top-bar.tsx
@@ -109,6 +109,10 @@ export function MvTopBar({
   const sidebarApps = useResolvedSidebarApps();
   const isStalwartAdmin = useStalwartAdmin();
   const hasUpdate = useUpdateStore(selectHasUpdate);
+  // The navigation rail starts the update check, and this bar replaces it on
+  // desktop; without this the admin shield's update dot never lights up.
+  const startUpdatePolling = useUpdateStore((s) => s.startPolling);
+  useEffect(() => { startUpdatePolling(); }, [startUpdatePolling]);
   const updateSeverity = useUpdateStore((s) => s.status?.severity);
   const updateImportant = updateSeverity === "security" || updateSeverity === "deprecated";
 

From 7533fc516b7b160f871d0f34e730dc5f67e8de35 Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Sat, 10 Oct 2026 19:24:43 +0200
Subject: [PATCH 21/23] fix: renew push for every connected account, not only
 the active one #1054

The background resync only touched the active client, so accounts
turned on from the all-accounts panel lapsed when the server's push
subscription expired after seven days. The resync now walks every
connected login in turn, active one first, and runs again once the
background logins finish connecting. Single-account behaviour is
unchanged.

The panel also lists which accounts failed to enable and why, instead
of only a count.
---
 .../push-notification-prompt.test.tsx         | 76 ++++++++++++++++++-
 components/push-notification-prompt.tsx       | 68 ++++++++++++++---
 .../__tests__/multi-account-push.test.tsx     | 39 +++++++++-
 components/settings/multi-account-push.tsx    | 33 +++++++-
 4 files changed, 200 insertions(+), 16 deletions(-)

diff --git a/components/__tests__/push-notification-prompt.test.tsx b/components/__tests__/push-notification-prompt.test.tsx
index d09e7d83b..fd71589b1 100644
--- a/components/__tests__/push-notification-prompt.test.tsx
+++ b/components/__tests__/push-notification-prompt.test.tsx
@@ -17,7 +17,12 @@ const mocks = vi.hoisted(() => ({
     username: "alice@example.com",
     isAuthenticated: true,
     isDemoMode: false,
+    connectedAccountsRevision: 0,
+    // Login id -> client, as the auth store keeps it for the account switcher.
+    connected: new Map<string, { getAccountId: () => string }>(),
+    getAllConnectedClients: () => new Map(mocks.authState.connected),
   },
+  accounts: [] as { id: string; username: string }[],
   settingsState: { emailNotificationsEnabled: true, pushRelayUrl: "" },
   policyState: {
     loaded: true,
@@ -34,8 +39,15 @@ vi.mock("next/navigation", () => ({
 }));
 
 vi.mock("@/stores/auth-store", () => ({
-  useAuthStore: (selector: (state: typeof mocks.authState) => unknown) =>
-    selector(mocks.authState),
+  useAuthStore: Object.assign(
+    (selector: (state: typeof mocks.authState) => unknown) =>
+      selector(mocks.authState),
+    { getState: () => mocks.authState },
+  ),
+}));
+
+vi.mock("@/stores/account-store", () => ({
+  useAccountStore: { getState: () => ({ accounts: mocks.accounts }) },
 }));
 
 vi.mock("@/stores/settings-store", () => ({
@@ -82,6 +94,9 @@ describe("PushNotificationPrompt", () => {
     mocks.supported = true;
     mocks.enabled = false;
     mocks.authState.client = { getAccountId: () => "account-1" };
+    mocks.authState.connectedAccountsRevision = 0;
+    mocks.authState.connected = new Map([["alice@mail.example.com", mocks.authState.client]]);
+    mocks.accounts = [{ id: "alice@mail.example.com", username: "alice@example.com" }];
     mocks.authState.username = "alice@example.com";
     mocks.authState.isAuthenticated = true;
     mocks.authState.isDemoMode = false;
@@ -188,6 +203,63 @@ describe("PushNotificationPrompt", () => {
     expect(mocks.enableWebPush).not.toHaveBeenCalled();
   });
 
+  it("renews push for every connected login, not only the active one", async () => {
+    // Push for bob was enabled from the all-accounts panel; he never becomes
+    // the active account, so only this background pass keeps his
+    // registration from hitting the server's 7-day expiry.
+    const bob = { getAccountId: () => "account-2" };
+    mocks.authState.connected.set("bob@mail.example.com", bob);
+    mocks.accounts.push({ id: "bob@mail.example.com", username: "bob@example.com" });
+
+    render(<PushNotificationPrompt />);
+    await advancePromptDelay();
+
+    expect(mocks.resyncWebPush).toHaveBeenCalledTimes(2);
+    expect(mocks.resyncWebPush.mock.calls[0][0]).toMatchObject({
+      client: mocks.authState.client,
+      accountLabel: "alice@example.com",
+    });
+    expect(mocks.resyncWebPush.mock.calls[1][0]).toMatchObject({
+      client: bob,
+      accountLabel: "bob@example.com",
+      relayBaseUrl: "https://notifications.relay.bulwarkmail.org",
+    });
+  });
+
+  it("renews the other logins again when the tab returns to the foreground", async () => {
+    const bob = { getAccountId: () => "account-2" };
+    mocks.authState.connected.set("bob@mail.example.com", bob);
+    render(<PushNotificationPrompt />);
+    await advancePromptDelay();
+    mocks.resyncWebPush.mockClear();
+
+    await act(async () => {
+      document.dispatchEvent(new Event("visibilitychange"));
+      await Promise.resolve();
+      await Promise.resolve();
+    });
+
+    expect(mocks.resyncWebPush.mock.calls.map(([p]) => p.client)).toEqual([
+      mocks.authState.client,
+      bob,
+    ]);
+  });
+
+  it("reaches logins that finish connecting after the first pass", async () => {
+    const { rerender } = render(<PushNotificationPrompt />);
+    await advancePromptDelay();
+    expect(mocks.resyncWebPush).toHaveBeenCalledTimes(1);
+
+    // The background restore connects bob and bumps the revision.
+    const bob = { getAccountId: () => "account-2" };
+    mocks.authState.connected.set("bob@mail.example.com", bob);
+    mocks.authState.connectedAccountsRevision = 1;
+    rerender(<PushNotificationPrompt />);
+    await advancePromptDelay();
+
+    expect(mocks.resyncWebPush.mock.calls.map(([p]) => p.client)).toContain(bob);
+  });
+
   it("does not touch push in demo mode", async () => {
     mocks.authState.isDemoMode = true;
     render(<PushNotificationPrompt />);
diff --git a/components/push-notification-prompt.tsx b/components/push-notification-prompt.tsx
index d43492cdc..fae24ee61 100644
--- a/components/push-notification-prompt.tsx
+++ b/components/push-notification-prompt.tsx
@@ -4,6 +4,7 @@ import { useCallback, useEffect, useLayoutEffect, useState } from "react";
 import { usePathname } from "next/navigation";
 import { useTranslations } from "next-intl";
 import { Bell, Loader2, X } from "@/components/icons";
+import { useAccountStore } from "@/stores/account-store";
 import { useAuthStore } from "@/stores/auth-store";
 import { usePolicyStore } from "@/stores/policy-store";
 import { useSettingsStore } from "@/stores/settings-store";
@@ -26,6 +27,37 @@ function dismissedKey(accountId: string): string {
   return `${DISMISSED_KEY_PREFIX}${accountId}`;
 }
 
+interface ResyncTarget {
+  client: NonNullable<ReturnType<typeof useAuthStore.getState>["client"]>;
+  accountLabel?: string;
+}
+
+/**
+ * Every login whose push registration this tab should keep alive: the active
+ * one first, then each other connected login. Push can be enabled for a login
+ * that is not on screen (the all-accounts panel in settings), and Stalwart
+ * expires a PushSubscription after 7 days, so renewing only the active login
+ * would let the others lapse. The other clients are the ones the auth store
+ * already keeps for the account switcher, so this opens no new connection;
+ * resyncWebPush itself skips logins without push in a local check.
+ */
+function resyncTargets(
+  activeClient: ResyncTarget["client"],
+  activeLabel: string | undefined,
+): ResyncTarget[] {
+  const targets: ResyncTarget[] = [{ client: activeClient, accountLabel: activeLabel }];
+  const auth = useAuthStore.getState();
+  const others = auth.getAllConnectedClients?.() ?? new Map();
+  if (others.size === 0) return targets;
+  const accounts = useAccountStore.getState().accounts;
+  for (const [loginId, other] of others) {
+    if (!other || other === activeClient) continue;
+    const account = accounts.find((a) => a.id === loginId);
+    targets.push({ client: other, accountLabel: account?.username });
+  }
+  return targets;
+}
+
 function isExcludedPath(pathname: string): boolean {
   return /(^|\/)settings(?:\/|$)/.test(pathname)
     || /(^|\/)setup(?:\/|$)/.test(pathname)
@@ -58,6 +90,11 @@ export function PushNotificationPrompt() {
   const username = useAuthStore((state) => state.username);
   const isAuthenticated = useAuthStore((state) => state.isAuthenticated);
   const isDemoMode = useAuthStore((state) => state.isDemoMode);
+  // Bumped when the background logins finish connecting: the renewal below
+  // re-runs then so it reaches them too.
+  const connectedAccountsRevision = useAuthStore(
+    (state) => state.connectedAccountsRevision,
+  );
   const emailNotificationsEnabled = useSettingsStore(
     (state) => state.emailNotificationsEnabled,
   );
@@ -121,21 +158,30 @@ export function PushNotificationPrompt() {
   // live registration stale.
   useEffect(() => {
     if (!policyLoaded || !isAuthenticated || !client || !accountId || isDemoMode) return;
-    const resync = () => {
-      void resyncWebPush({
-        client,
-        relayBaseUrl,
-        accountLabel: username ?? undefined,
-        inboxOnly: pushNotifyInboxOnly,
-      });
+    let cancelled = false;
+    const resync = async () => {
+      // One login at a time: they share the browser's single
+      // PushSubscription, and a parallel re-create would race on it.
+      for (const target of resyncTargets(client, username ?? undefined)) {
+        if (cancelled) return;
+        await resyncWebPush({
+          client: target.client,
+          relayBaseUrl,
+          accountLabel: target.accountLabel,
+          inboxOnly: pushNotifyInboxOnly,
+        });
+      }
     };
-    resync();
+    void resync();
     // A long-open tab comes back to the foreground: renew the subscription
     // before the server's 7-day expiry (resyncWebPush runs at most daily).
-    const onVisible = () => { if (document.visibilityState === 'visible') resync(); };
+    const onVisible = () => { if (document.visibilityState === 'visible') void resync(); };
     document.addEventListener('visibilitychange', onVisible);
-    return () => document.removeEventListener('visibilitychange', onVisible);
-  }, [accountId, client, isAuthenticated, isDemoMode, policyLoaded, pushNotifyInboxOnly, relayBaseUrl, username]);
+    return () => {
+      cancelled = true;
+      document.removeEventListener('visibilitychange', onVisible);
+    };
+  }, [accountId, client, connectedAccountsRevision, isAuthenticated, isDemoMode, policyLoaded, pushNotifyInboxOnly, relayBaseUrl, username]);
 
   useEffect(() => {
     let cancelled = false;
diff --git a/components/settings/__tests__/multi-account-push.test.tsx b/components/settings/__tests__/multi-account-push.test.tsx
index 1c3f01eaf..202078635 100644
--- a/components/settings/__tests__/multi-account-push.test.tsx
+++ b/components/settings/__tests__/multi-account-push.test.tsx
@@ -1,4 +1,4 @@
-import { render, waitFor } from '@testing-library/react';
+import { fireEvent, render, screen, waitFor } from '@testing-library/react';
 import { describe, it, expect, vi } from 'vitest';
 import { MultiAccountPushSettings } from '../multi-account-push';
 import { useAccountStore } from '@/stores/account-store';
@@ -6,7 +6,8 @@ import { useAuthStore } from '@/stores/auth-store';
 import * as webPush from '@/lib/web-push';
 
 vi.mock('next-intl', () => ({
-  useTranslations: () => (key: string) => key,
+  useTranslations: () => (key: string, values?: Record<string, unknown>) =>
+    values ? `${key} ${JSON.stringify(values)}` : key,
 }));
 
 vi.mock('../settings-section', async (importOriginal) => ({
@@ -44,4 +45,38 @@ describe('MultiAccountPushSettings', () => {
     expect(webPush.isWebPushEnabled).toHaveBeenCalledWith('jmap-a');
     expect(webPush.isWebPushEnabled).not.toHaveBeenCalledWith('a@mail.example.com');
   });
+
+  it('names each account the bulk enable left off, with the reason', async () => {
+    const clients: Record<string, { getAccountId: () => string }> = {
+      'a@mail.example.com': { getAccountId: () => 'jmap-a' },
+      'b@mail.example.com': { getAccountId: () => 'jmap-b' },
+      'c@mail.example.com': { getAccountId: () => 'jmap-c' },
+    };
+    useAccountStore.setState({
+      accounts: [
+        { id: 'a@mail.example.com', username: 'a', email: 'a@example.com', displayName: 'Alice', isConnected: true },
+        { id: 'b@mail.example.com', username: 'b', email: 'b@example.com', displayName: 'Bob', isConnected: true },
+        { id: 'c@mail.example.com', username: 'c', email: 'c@example.com', displayName: 'Carol', isConnected: true },
+      ] as never,
+    });
+    useAuthStore.setState({ getClientForAccount: ((id: string) => clients[id]) as never });
+    vi.mocked(webPush.enableWebPushForAccounts).mockResolvedValueOnce({
+      enabled: ['a@mail.example.com'],
+      failed: [
+        { accountId: 'b@mail.example.com', error: new Error('relay unreachable') },
+        { accountId: 'c@mail.example.com', error: 'timeout' },
+      ],
+    });
+
+    render(<MultiAccountPushSettings />);
+    await waitFor(() => expect(screen.getByText('select_all')).toBeInTheDocument());
+    fireEvent.click(screen.getByLabelText('select_all'));
+    fireEvent.click(screen.getByText('enable_selected'));
+
+    const alert = await screen.findByRole('alert');
+    expect(screen.getByText(/result_partial/).textContent).toContain('"enabled":1,"failed":2');
+    expect(alert.textContent).toContain('Bob (b@example.com): relay unreachable');
+    expect(alert.textContent).toContain('Carol (c@example.com): timeout');
+    expect(alert.textContent).not.toContain('Alice');
+  });
 });
diff --git a/components/settings/multi-account-push.tsx b/components/settings/multi-account-push.tsx
index edf4711a1..9df3bfa4b 100644
--- a/components/settings/multi-account-push.tsx
+++ b/components/settings/multi-account-push.tsx
@@ -10,6 +10,18 @@ import { useAuthStore } from '@/stores/auth-store';
 import { useSettingsStore } from '@/stores/settings-store';
 import { disableWebPush, enableWebPushForAccounts, isWebPushEnabled, isWebPushSupported } from '@/lib/web-push';
 
+interface FailedAccount {
+  id: string;
+  name: string;
+  email: string;
+  reason: string;
+}
+
+function failureReason(error: unknown): string {
+  if (error instanceof Error && error.message) return error.message;
+  return String(error);
+}
+
 /**
  * Turn push on or off for several accounts at once.
  *
@@ -27,6 +39,9 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
   const [chosen, setChosen] = useState<Set<string>>(new Set());
   const [busy, setBusy] = useState(false);
   const [notice, setNotice] = useState('');
+  // Which accounts the last bulk enable left off, and why: a bare count
+  // leaves the user guessing which login to retry.
+  const [failures, setFailures] = useState<FailedAccount[]>([]);
 
   const connected = accounts.filter(a => a.isConnected && useAuthStore.getState().getClientForAccount(a.id));
 
@@ -56,7 +71,7 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
     const auth = useAuthStore.getState();
     const targets = connected.filter(a => chosen.has(a.id));
     if (!targets.length) return;
-    setBusy(true); setNotice('');
+    setBusy(true); setNotice(''); setFailures([]);
     try {
       if (action === 'enable') {
         const outcome = await enableWebPushForAccounts(
@@ -66,6 +81,15 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
         setNotice(outcome.failed.length
           ? t('result_partial', { enabled: outcome.enabled.length, failed: outcome.failed.length })
           : t('result_enabled', { count: outcome.enabled.length }));
+        setFailures(outcome.failed.map(({ accountId, error }) => {
+          const account = targets.find(a => a.id === accountId);
+          return {
+            id: accountId,
+            name: account ? (account.displayName || account.label || account.username) : accountId,
+            email: account ? (account.email || account.username) : '',
+            reason: failureReason(error),
+          };
+        }));
       } else {
         // Teardown swallows its own failures, so every account ends up local-off.
         for (const account of targets) {
@@ -112,6 +136,13 @@ export function MultiAccountPushSettings({ relayBaseUrl }: { relayBaseUrl?: stri
         </Button>
       </div>
       {notice && <p className="text-sm text-muted-foreground">{notice}</p>}
+      {failures.length > 0 && <ul role="alert" className="space-y-1 text-sm text-destructive">
+        {failures.map(f => <li key={f.id}>
+          <span className="font-medium">{f.name}</span>
+          {f.email && f.email !== f.name && <span> ({f.email})</span>}
+          <span>: {f.reason}</span>
+        </li>)}
+      </ul>}
     </div>
   </SettingsSection>;
 }

From 7cbd33dbc870f64f0a1ef736f1133119ba335b53 Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Sat, 10 Oct 2026 21:51:19 +0200
Subject: [PATCH 22/23] fix: act on the ticked account's mail in batch actions
 #1061

Batch delete grouped the selection by bare email id, so with the same
id in two accounts, permanent-deleting B's row destroyed A's message
and left B's alone. Copy had the same lookup and went out through the
wrong account.

- resolve the selection to email objects by key, including ticked
  members of an expanded thread that are not list rows
- delete, move, mark read, tag and copy group by those objects
- rows, thread checkboxes, drag and drop compare by key, so ticked
  rows show as checked in unified and tag views
- the Mountain View toolbar uses the same resolver
---
 .../email/__tests__/thread-list-item.test.tsx |  66 +++++++-
 components/email/email-list.tsx               |  14 +-
 components/email/mv-list-toolbar.tsx          |   6 +-
 components/email/thread-email-item.tsx        |   4 +-
 components/email/thread-list-item.tsx         |  14 +-
 components/mail/mail-app.tsx                  |   8 +-
 hooks/use-email-drag.ts                       |  11 +-
 hooks/use-mailbox-drop.ts                     |   6 +-
 .../__tests__/email-batch-namesakes.test.ts   | 154 ++++++++++++++++++
 stores/email-store.ts                         |  77 ++++++---
 10 files changed, 306 insertions(+), 54 deletions(-)
 create mode 100644 stores/__tests__/email-batch-namesakes.test.ts

diff --git a/components/email/__tests__/thread-list-item.test.tsx b/components/email/__tests__/thread-list-item.test.tsx
index 2807d0bfd..aabbd2415 100644
--- a/components/email/__tests__/thread-list-item.test.tsx
+++ b/components/email/__tests__/thread-list-item.test.tsx
@@ -4,7 +4,7 @@ import { ThreadListItem } from '../thread-list-item';
 import { useSettingsStore, DEFAULT_KEYWORDS } from '@/stores/settings-store';
 import { useEmailStore } from '@/stores/email-store';
 import { useUIStore } from '@/stores/ui-store';
-import { groupEmailsByThread } from '@/lib/thread-utils';
+import { emailKeyFor, groupEmailsByThread } from '@/lib/thread-utils';
 import type { Email } from '@/lib/jmap/types';
 
 vi.mock('@/hooks/use-email-drag', () => ({
@@ -439,3 +439,67 @@ describe('ThreadListItem account row tint', () => {
     expect(row(container)!.className).toContain('bg-teal-100');
   });
 });
+
+describe('ThreadListItem selection in a merged view', () => {
+  // Unified and tag views stamp each email with its owning account, and the
+  // selection holds `emailKeyFor` keys. A bare-id check never matches them.
+  const stamp = { sourceClientAccountId: 'account-b', sourceAccountId: 'account-b' };
+
+  beforeEach(() => {
+    useSettingsStore.setState({
+      emailKeywords: [...DEFAULT_KEYWORDS],
+      showPreview: false,
+      mailLayout: 'split',
+      density: 'regular',
+    });
+    useEmailStore.setState({
+      isUnifiedView: true,
+      selectedEmailKeys: new Set<string>(),
+      lastSelectedEmailKey: null,
+      selectedMailbox: '',
+    });
+  });
+
+  it('shows a ticked stamped row as checked', () => {
+    const email = makeEmail({ ...stamp });
+    useEmailStore.setState({ emails: [email], selectedEmailKeys: new Set([emailKeyFor(email)]) });
+    renderRow(email);
+
+    expect(screen.getByRole('checkbox')).toHaveAttribute('aria-checked', 'true');
+  });
+
+  it('does not show a namesake row from another account as checked', () => {
+    const mine = makeEmail({ sourceClientAccountId: 'account-a', sourceAccountId: 'account-a' });
+    const theirs = makeEmail({ ...stamp });
+    useEmailStore.setState({ emails: [mine, theirs], selectedEmailKeys: new Set([emailKeyFor(mine)]) });
+    renderRow(theirs);
+
+    expect(screen.getByRole('checkbox')).toHaveAttribute('aria-checked', 'false');
+  });
+
+  it('ticks a whole thread by key and shows it checked', () => {
+    const e1 = makeEmail({ id: 'e1', threadId: 't1', receivedAt: '2024-01-15T10:00:00Z', ...stamp });
+    const e2 = makeEmail({ id: 'e2', threadId: 't1', receivedAt: '2024-01-15T11:00:00Z', ...stamp });
+    useEmailStore.setState({ emails: [e1, e2] });
+    const [thread] = groupEmailsByThread([e1, e2]);
+    const ui = (
+      <ThreadListItem thread={thread} isExpanded={false} onToggleExpand={() => {}} onEmailSelect={() => {}} />
+    );
+    const { rerender } = render(ui);
+
+    act(() => {
+      screen.getByRole('checkbox').dispatchEvent(new MouseEvent('click', { bubbles: true }));
+    });
+
+    const { selectedEmailKeys, lastSelectedEmailKey } = useEmailStore.getState();
+    expect([...selectedEmailKeys].sort()).toEqual([emailKeyFor(e1), emailKeyFor(e2)].sort());
+    expect(lastSelectedEmailKey).toBe(emailKeyFor(e2));
+    rerender(ui);
+    expect(screen.getByRole('checkbox')).toHaveAttribute('aria-checked', 'true');
+
+    act(() => {
+      screen.getByRole('checkbox').dispatchEvent(new MouseEvent('click', { bubbles: true }));
+    });
+    expect(useEmailStore.getState().selectedEmailKeys.size).toBe(0);
+  });
+});
diff --git a/components/email/email-list.tsx b/components/email/email-list.tsx
index 17d02e328..df676ebb3 100644
--- a/components/email/email-list.tsx
+++ b/components/email/email-list.tsx
@@ -13,7 +13,7 @@ import { Trash2, Mail, MailX, MailOpen, Loader2, SearchX, AlertTriangle, Calenda
 import { useState, useEffect, useLayoutEffect, useRef, useCallback, useMemo } from "react";
 import { Button } from "@/components/ui/button";
 import { ConfirmDialog } from "@/components/ui/confirm-dialog";
-import { useEmailStore, ArchiveMailboxNotFoundError } from "@/stores/email-store";
+import { useEmailStore, ArchiveMailboxNotFoundError, resolveSelectedEmails } from "@/stores/email-store";
 import { useAuthStore } from "@/stores/auth-store";
 import { useAccountStore } from "@/stores/account-store";
 import { useSettingsStore } from "@/stores/settings-store";
@@ -400,7 +400,7 @@ export function EmailList({
     if (!client || isProcessing) return;
     setIsProcessing(true);
     try {
-      const emailIds = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
+      const emailIds = resolveSelectedEmails(useEmailStore.getState()).map(e => e.id);
       await batchUndoSpam(client, emailIds);
       toast.success(tSpam('toast_not_spam_batch', { count: emailIds.length }));
     } catch {
@@ -812,9 +812,11 @@ export function EmailList({
           onRescheduleScheduled={onRescheduleScheduled ? () => onRescheduleScheduled(contextMenuEmail!) : undefined}
           copyTargets={copyTargets}
           onCopyToAccount={async (accountId, mailboxId) => {
+            // Pass the emails, not their ids: an id alone cannot say which
+            // account's namesake to copy.
             const ids = selectedEmailKeys.has(emailKeyFor(contextMenuEmail!)) && selectedEmailKeys.size > 1
-              ? emails.filter((email) => selectedEmailKeys.has(emailKeyFor(email))).map((email) => email.id)
-              : [contextMenuEmail!.id];
+              ? resolveSelectedEmails(useEmailStore.getState())
+              : [contextMenuEmail!];
             const target = accountMailboxes[accountId]?.find((mb) => mb.id === mailboxId);
             await runBatchEmailAction(() => copyEmailsToAccount(ids, accountId, target?.originalId ?? mailboxId), {
               success: tNotifications('emails_copied', { count: ids.length }),
@@ -854,7 +856,7 @@ export function EmailList({
           }}
           onBatchMarkAsSpam={async () => {
             if (client) {
-              const emailIds = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
+              const emailIds = resolveSelectedEmails(useEmailStore.getState()).map(e => e.id);
               try {
                 await batchMarkAsSpam(client, emailIds);
                 toast.success(
@@ -867,7 +869,7 @@ export function EmailList({
           }}
           onBatchUndoSpam={async () => {
             if (client) {
-              const emailIds = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
+              const emailIds = resolveSelectedEmails(useEmailStore.getState()).map(e => e.id);
               try {
                 await batchUndoSpam(client, emailIds);
                 toast.success(
diff --git a/components/email/mv-list-toolbar.tsx b/components/email/mv-list-toolbar.tsx
index e8066ae74..d5fd11836 100644
--- a/components/email/mv-list-toolbar.tsx
+++ b/components/email/mv-list-toolbar.tsx
@@ -19,7 +19,7 @@ import {
 } from "@/components/icons";
 import { useTranslations } from "next-intl";
 import { useAuthStore } from "@/stores/auth-store";
-import { useEmailStore, ArchiveMailboxNotFoundError } from "@/stores/email-store";
+import { useEmailStore, ArchiveMailboxNotFoundError, resolveSelectedEmails } from "@/stores/email-store";
 import { runBatchEmailAction } from "@/lib/email-action-toast";
 import { toast } from "@/stores/toast-store";
 import { useConfirmDialog } from "@/hooks/use-confirm-dialog";
@@ -247,7 +247,7 @@ export function MvListToolbar({
       });
     });
 
-  const selectedEmails = emails.filter((email) => selectedEmailKeys.has(email.id));
+  const selectedEmails = resolveSelectedEmails(useEmailStore.getState());
 
   // The same targets the row's own context menu offers, with the account of
   // the selection leading (#1149).
@@ -320,7 +320,7 @@ export function MvListToolbar({
   const handleSpam = () =>
     run(async () => {
       if (!client) return;
-      const ids = Array.from(selectedEmailKeys);
+      const ids = resolveSelectedEmails(useEmailStore.getState()).map((email) => email.id);
       try {
         if (isInJunk) {
           await batchUndoSpam(client, ids);
diff --git a/components/email/thread-email-item.tsx b/components/email/thread-email-item.tsx
index 4a4a726de..83f54244d 100644
--- a/components/email/thread-email-item.tsx
+++ b/components/email/thread-email-item.tsx
@@ -12,7 +12,7 @@ import { useLongPress } from "@/hooks/use-long-press";
 import { useEmailStore } from "@/stores/email-store";
 import { useSettingsStore } from "@/stores/settings-store";
 import { useUIStore } from "@/stores/ui-store";
-import { getEmailTagIds } from "@/lib/thread-utils";
+import { emailKeyFor, getEmailTagIds } from "@/lib/thread-utils";
 import { useKeywordFormat } from "@/hooks/use-keyword-format";
 import { useTagDisplay } from "@/hooks/use-tag-display";
 import { TagBadge } from "./tag-badge";
@@ -47,7 +47,7 @@ export function ThreadEmailItem({
   const sender = email.from?.[0];
   const { selectedMailbox, selectedEmailKeys, toggleEmailSelection, selectRangeEmails, clearSelection } = useEmailStore();
   const density = useSettingsStore((state) => state.density);
-  const isChecked = selectedEmailKeys.has(email.id);
+  const isChecked = selectedEmailKeys.has(emailKeyFor(email));
 
   const { dragHandlers, isDragging } = useEmailDrag({
     email,
diff --git a/components/email/thread-list-item.tsx b/components/email/thread-list-item.tsx
index 655f9924b..5a2a9d638 100644
--- a/components/email/thread-list-item.tsx
+++ b/components/email/thread-list-item.tsx
@@ -17,7 +17,7 @@ import { accountTintKey, generateAvatarColor } from "@/lib/account-utils";
 import { useUIStore } from "@/stores/ui-store";
 import { useEmailStore } from "@/stores/email-store";
 import { useAccountStore, type AccountEntry } from "@/stores/account-store";
-import { getThreadTagIds, getEmailTagIds } from "@/lib/thread-utils";
+import { emailKeyFor, getThreadTagIds, getEmailTagIds } from "@/lib/thread-utils";
 import { useKeywordFormat } from "@/hooks/use-keyword-format";
 import { useTagDisplay } from "@/hooks/use-tag-display";
 import { TagBadge, TAG_GROUP_CLASS, TAG_LOZENGE_CLASS } from "./tag-badge";
@@ -306,7 +306,7 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
     const account = email.accountId ? getAccountById(email.accountId) : undefined;
     const accountColor = account?.avatarColor;
     const accountDescription = describeAccount(email.accountLabel, account);
-    const isChecked = selectedEmailKeys.has(email.id);
+    const isChecked = selectedEmailKeys.has(emailKeyFor(email));
     const isMobile = useUIStore((state) => state.isMobile);
     // The horizontal one-line "focus" layout doesn't fit on narrow screens; fall back to multi-line on mobile.
     const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
@@ -879,7 +879,7 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
     const isSelected = selectedEmailId === latestEmail.id ||
       thread.emails.some(e => e.id === selectedEmailId);
 
-    const isChecked = thread.emails.some(e => selectedEmailKeys.has(e.id));
+    const isChecked = thread.emails.some(e => selectedEmailKeys.has(emailKeyFor(e)));
 
     if (emailCount === 1) {
       return (
@@ -909,16 +909,16 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
 
     // Toggle selection for all emails in this thread.
     const toggleThreadSelection = () => {
-      const allSelected = thread.emails.every(em => selectedEmailKeys.has(em.id));
+      const allSelected = thread.emails.every(em => selectedEmailKeys.has(emailKeyFor(em)));
       const newSelection = new Set(selectedEmailKeys);
       thread.emails.forEach(em => {
         if (allSelected) {
-          newSelection.delete(em.id);
+          newSelection.delete(emailKeyFor(em));
         } else {
-          newSelection.add(em.id);
+          newSelection.add(emailKeyFor(em));
         }
       });
-      useEmailStore.setState({ selectedEmailKeys: newSelection, lastSelectedEmailKey: latestEmail.id });
+      useEmailStore.setState({ selectedEmailKeys: newSelection, lastSelectedEmailKey: emailKeyFor(latestEmail) });
     };
 
     const handleThreadCheckboxClick = (e: React.MouseEvent) => {
diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index 8ccb50440..a742c738f 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -32,7 +32,7 @@ import { usePolicyStore } from "@/stores/policy-store";
 import type { UnifiedAccountClient } from "@/lib/unified-mailbox";
 import { connectedAccountsGrew } from "@/lib/unified-mailbox";
 import { KeyboardShortcutsModal } from "@/components/keyboard-shortcuts-modal";
-import { useEmailStore, buildUnifiedAccountClients, invalidateUnifiedMailboxes, captureViewToken, ArchiveMailboxNotFoundError, ensureArchiveMailbox, resolveUnstampedEmailAccountId, resolveEmailBlobContext, emptyFolderMovesToTrash } from "@/stores/email-store";
+import { useEmailStore, buildUnifiedAccountClients, invalidateUnifiedMailboxes, captureViewToken, ArchiveMailboxNotFoundError, ensureArchiveMailbox, resolveSelectedEmails, resolveUnstampedEmailAccountId, resolveEmailBlobContext, emptyFolderMovesToTrash } from "@/stores/email-store";
 import { groupSearchScopeFolders, SEARCH_SCOPE_ALL_FOLDERS } from "@/lib/search-scope-folders";
 import { toast } from "@/stores/toast-store";
 import { formatRejectedRecipients, type JMAPClient } from "@/lib/jmap/client";
@@ -59,7 +59,7 @@ import { debug } from "@/lib/debug";
 import { playNotificationSound } from "@/lib/notification-sound";
 import { cn, getMailboxPath } from "@/lib/utils";
 import { localizeMailboxName } from "@/lib/mailbox-label";
-import { KEYWORD_PREFIX, KEYWORD_PREFIX_LEGACY, emailKeyFor, groupEmailsByThread, threadKeyFor } from "@/lib/thread-utils";
+import { KEYWORD_PREFIX, KEYWORD_PREFIX_LEGACY, groupEmailsByThread, threadKeyFor } from "@/lib/thread-utils";
 import { resolveThreadRoute } from "@/lib/thread-routing";
 import {
   ErrorBoundary,
@@ -849,8 +849,8 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
       const isInJunk = currentMailbox?.role === 'junk';
       if (selectedEmailKeys.size > 0 && client) {
         // The spam actions take bare ids of the viewed account: resolve the
-        // selection keys through the loaded rows.
-        const ids = useEmailStore.getState().emails.filter(e => selectedEmailKeys.has(emailKeyFor(e))).map(e => e.id);
+        // selection keys through the loaded rows and thread members.
+        const ids = resolveSelectedEmails(useEmailStore.getState()).map(e => e.id);
         try {
           if (isInJunk) {
             await batchUndoSpam(client, ids);
diff --git a/hooks/use-email-drag.ts b/hooks/use-email-drag.ts
index 0bea4c299..1a0c8cdee 100644
--- a/hooks/use-email-drag.ts
+++ b/hooks/use-email-drag.ts
@@ -4,6 +4,7 @@ import { useCallback, useEffect, useMemo, useRef, DragEvent } from "react";
 import { Email } from "@/lib/jmap/types";
 import { IJMAPClient } from "@/lib/jmap/client-interface";
 import { useEmailStore } from "@/stores/email-store";
+import { emailKeyFor } from "@/lib/thread-utils";
 import { useAuthStore } from "@/stores/auth-store";
 import { useDragDropContext } from "@/contexts/drag-drop-context";
 import { useUIStore } from "@/stores/ui-store";
@@ -195,10 +196,10 @@ export function useEmailDrag({ email, sourceMailboxId, threadEmails }: UseEmailD
 
   const handlePointerEnter = useCallback(() => {
     if (!dragOutEnabled || !client) return;
-    const isSelected = selectedEmailKeys.has(email.id);
+    const isSelected = selectedEmailKeys.has(emailKeyFor(email));
     const isMulti = isSelected && selectedEmailKeys.size > 1;
     if (isMulti) {
-      const selected = emails.filter((em) => selectedEmailKeys.has(em.id));
+      const selected = emails.filter((em) => selectedEmailKeys.has(emailKeyFor(em)));
       // Only worth bundling when at least one selected email has a blobId.
       if (selected.some((em) => em.blobId)) {
         prefetchEmailBundle(client, selected, filenameOptions, bundleOptions);
@@ -206,16 +207,16 @@ export function useEmailDrag({ email, sourceMailboxId, threadEmails }: UseEmailD
     } else {
       prefetchSingle();
     }
-  }, [dragOutEnabled, client, selectedEmailKeys, email.id, emails, prefetchSingle, filenameOptions, bundleOptions]);
+  }, [dragOutEnabled, client, selectedEmailKeys, email, emails, prefetchSingle, filenameOptions, bundleOptions]);
 
   const handleDragStart = useCallback((e: DragEvent<HTMLDivElement>) => {
     // Determine which emails to drag:
     // - If current email is selected, drag all selected
     // - If threadEmails provided (thread header), drag all thread emails
     // - Otherwise, drag only this email
-    const isSelected = selectedEmailKeys.has(email.id);
+    const isSelected = selectedEmailKeys.has(emailKeyFor(email));
     const emailsToDrag = isSelected
-      ? emails.filter(em => selectedEmailKeys.has(em.id))
+      ? emails.filter(em => selectedEmailKeys.has(emailKeyFor(em)))
       : threadEmails || [email];
 
     e.dataTransfer.effectAllowed = "copyMove";
diff --git a/hooks/use-mailbox-drop.ts b/hooks/use-mailbox-drop.ts
index 2b87b6665..61c6792f8 100644
--- a/hooks/use-mailbox-drop.ts
+++ b/hooks/use-mailbox-drop.ts
@@ -3,6 +3,7 @@
 import { useCallback, useState, DragEvent } from "react";
 import { Mailbox, Email } from "@/lib/jmap/types";
 import { useEmailStore } from "@/stores/email-store";
+import { emailKeyFor } from "@/lib/thread-utils";
 import { useAuthStore } from "@/stores/auth-store";
 import { useDragDropContext } from "@/contexts/drag-drop-context";
 import { toast } from "@/stores/toast-store";
@@ -183,8 +184,9 @@ export function useMailboxDrop({ mailbox, onDropComplete, onSuccess, onError }:
         await moveEmailsToMailbox(client, emailIds, mailbox.id);
       }
 
-      // Clear selection if any selected emails were moved
-      if (emailIds.some(id => selectedEmailKeys.has(id))) {
+      // Clear selection if any selected emails were moved. The selection is
+      // keyed by owning account, so compare the dragged emails, not their ids.
+      if (draggedEmails.some(em => selectedEmailKeys.has(emailKeyFor(em)))) {
         clearSelection();
       }
 
diff --git a/stores/__tests__/email-batch-namesakes.test.ts b/stores/__tests__/email-batch-namesakes.test.ts
new file mode 100644
index 000000000..4ffae0142
--- /dev/null
+++ b/stores/__tests__/email-batch-namesakes.test.ts
@@ -0,0 +1,154 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { useEmailStore, resolveSelectedEmails } from '../email-store';
+import { useAuthStore } from '../auth-store';
+import { emailKeyFor } from '@/lib/thread-utils';
+import type { Email, Mailbox } from '@/lib/jmap/types';
+import type { IJMAPClient } from '@/lib/jmap/client-interface';
+
+/**
+ * Batch actions over a selection that holds a namesake: the same email id in
+ * two accounts of the unified view. Each action must reach the account of the
+ * row that was ticked, through that account's client, and leave the other
+ * account's message alone.
+ */
+const twin = (account: string, overrides: Partial<Email> = {}): Email => ({
+  id: 'eiaaaabc', threadId: 'taaaabc', blobId: `blob-${account}`,
+  mailboxIds: { [`inbox-${account}`]: true }, keywords: {},
+  from: [{ email: `someone@${account}` }], to: [], subject: account,
+  receivedAt: '2026-09-19T08:00:00Z', size: 42, preview: '', hasAttachment: false,
+  sourceClientAccountId: account, sourceAccountId: account,
+  ...overrides,
+} as unknown as Email);
+
+const mailbox = (overrides: Partial<Mailbox>): Mailbox => ({
+  id: 'inbox', name: 'Inbox', sortOrder: 0,
+  totalEmails: 0, unreadEmails: 0, totalThreads: 0, unreadThreads: 0,
+  myRights: {
+    mayReadItems: true, mayAddItems: true, mayRemoveItems: true, maySetSeen: true,
+    maySetKeywords: true, mayCreateChild: true, mayRename: true, mayDelete: true, maySubmit: true,
+  },
+  isSubscribed: true, isShared: false,
+  ...overrides,
+} as Mailbox);
+
+const makeClient = () => ({
+  batchDeleteEmails: vi.fn().mockResolvedValue(undefined),
+  batchMoveEmails: vi.fn().mockResolvedValue(undefined),
+  batchMarkAsRead: vi.fn().mockResolvedValue(undefined),
+  getMailboxes: vi.fn().mockResolvedValue([]),
+}) as unknown as IJMAPClient & Record<string, ReturnType<typeof vi.fn>>;
+
+const a = twin('account-a');
+const b = twin('account-b');
+let clientA: ReturnType<typeof makeClient>;
+let clientB: ReturnType<typeof makeClient>;
+
+beforeEach(() => {
+  clientA = makeClient();
+  clientB = makeClient();
+  useAuthStore.setState({
+    activeAccountId: 'account-a',
+    client: clientA,
+    getClientForAccount: (id: string) =>
+      (id === 'account-a' ? clientA : id === 'account-b' ? clientB : undefined) as never,
+  } as never);
+  useEmailStore.setState({
+    isUnifiedView: true,
+    selectedMailbox: '',
+    selectedKeyword: null,
+    emails: [a, b],
+    threadEmailsCache: new Map(),
+    selectedEmailKeys: new Set(),
+    lastSelectedEmailKey: null,
+    mailboxes: [],
+    accountMailboxes: {
+      'account-a': [mailbox({ id: 'trash-a', name: 'Trash', role: 'trash', accountId: 'account-a' })],
+      'account-b': [mailbox({ id: 'trash-b', name: 'Trash', role: 'trash', accountId: 'account-b' })],
+    },
+    error: null,
+  });
+});
+
+describe('batch actions with a namesake in another account', () => {
+  it('permanently deletes only the ticked account copy', async () => {
+    useEmailStore.getState().toggleEmailSelection(b);
+    await useEmailStore.getState().batchDelete(clientA, true);
+
+    expect(clientB.batchDeleteEmails).toHaveBeenCalledWith(['eiaaaabc'], 'account-b');
+    expect(clientA.batchDeleteEmails).not.toHaveBeenCalled();
+    expect(useEmailStore.getState().emails.map(e => e.sourceAccountId)).toEqual(['account-a']);
+  });
+
+  it('moves only the ticked account copy to its own trash', async () => {
+    useEmailStore.getState().toggleEmailSelection(b);
+    await useEmailStore.getState().batchDelete(clientA);
+
+    expect(clientB.batchMoveEmails).toHaveBeenCalledWith(['eiaaaabc'], 'trash-b', 'account-b', false);
+    expect(clientA.batchMoveEmails).not.toHaveBeenCalled();
+    expect(useEmailStore.getState().emails.map(e => e.sourceAccountId)).toEqual(['account-a']);
+  });
+
+  it('keeps the namesake whose account has no trash when the other one moved', async () => {
+    useEmailStore.setState({
+      accountMailboxes: {
+        'account-a': [],
+        'account-b': [mailbox({ id: 'trash-b', name: 'Trash', role: 'trash', accountId: 'account-b' })],
+      },
+    });
+    useEmailStore.getState().selectAllEmails();
+    await useEmailStore.getState().batchDelete(clientA);
+
+    expect(clientB.batchMoveEmails).toHaveBeenCalledTimes(1);
+    expect(clientA.batchMoveEmails).not.toHaveBeenCalled();
+    const state = useEmailStore.getState();
+    expect(state.emails.map(e => e.sourceAccountId)).toEqual(['account-a']);
+    expect(state.error).toMatch(/trash folder missing/);
+  });
+
+  it('marks only the ticked account copy read', async () => {
+    useEmailStore.getState().toggleEmailSelection(b);
+    await useEmailStore.getState().batchMarkAsRead(clientA, true);
+
+    expect(clientB.batchMarkAsRead).toHaveBeenCalledWith(['eiaaaabc'], true, 'account-b');
+    expect(clientA.batchMarkAsRead).not.toHaveBeenCalled();
+    const [rowA, rowB] = useEmailStore.getState().emails;
+    expect(rowA.keywords.$seen).toBeUndefined();
+    expect(rowB.keywords.$seen).toBe(true);
+  });
+
+  it('copies the ticked account copy from its own account', async () => {
+    const crossAccountMoveEmails = vi.fn().mockResolvedValue(undefined);
+    useEmailStore.setState({ crossAccountMoveEmails });
+    await useEmailStore.getState().copyEmailsToAccount([b], 'account-c', 'dest');
+
+    expect(crossAccountMoveEmails).toHaveBeenCalledTimes(1);
+    const [bySource, , , , sourceJmap] = crossAccountMoveEmails.mock.calls[0];
+    expect([...bySource]).toEqual([['account-b', ['eiaaaabc']]]);
+    expect(sourceJmap).toBe('account-b');
+  });
+});
+
+describe('selection reaching expanded thread members', () => {
+  const row = { ...a, id: 'row', threadId: 'thr' } as Email;
+  const member = { ...a, id: 'member', threadId: 'thr' } as Email;
+
+  it('resolves a ticked member that is not a list row, once', () => {
+    const state = {
+      emails: [row],
+      threadEmailsCache: new Map([['k', [row, member]]]),
+      selectedEmailKeys: new Set([emailKeyFor(row), emailKeyFor(member)]),
+    };
+    expect(resolveSelectedEmails(state).map(e => e.id)).toEqual(['row', 'member']);
+  });
+
+  it('deletes a ticked member that lives outside the list', async () => {
+    useEmailStore.setState({
+      emails: [row],
+      threadEmailsCache: new Map([['account-a/account-a:thr', [row, member]]]),
+      selectedEmailKeys: new Set([emailKeyFor(member)]),
+    });
+    await useEmailStore.getState().batchDelete(clientA, true);
+
+    expect(clientA.batchDeleteEmails).toHaveBeenCalledWith(['member'], 'account-a');
+  });
+});
diff --git a/stores/email-store.ts b/stores/email-store.ts
index 251435f27..299735205 100644
--- a/stores/email-store.ts
+++ b/stores/email-store.ts
@@ -56,6 +56,28 @@ function dropFromSelection(
   return next;
 }
 
+/**
+ * The emails behind a key-based selection, each once. Looks in the list and in
+ * the loaded members of expanded threads: a thread member ticked in a folder
+ * view may live in another folder and so never be a list row.
+ */
+export function resolveSelectedEmails(state: {
+  emails: Email[];
+  threadEmailsCache: Map<string, Email[]>;
+  selectedEmailKeys: Set<string>;
+}): Email[] {
+  const { selectedEmailKeys } = state;
+  if (selectedEmailKeys.size === 0) return [];
+  const found = new Map<string, Email>();
+  const visit = (email: Email) => {
+    const key = emailKeyFor(email);
+    if (selectedEmailKeys.has(key) && !found.has(key)) found.set(key, email);
+  };
+  state.emails.forEach(visit);
+  for (const members of state.threadEmailsCache.values()) members.forEach(visit);
+  return [...found.values()];
+}
+
 /** Enough of an email to key a selection by its owning account. */
 type SelectableEmail = Pick<Email, 'id' | 'sourceClientAccountId' | 'sourceAccountId'>;
 
@@ -307,7 +329,8 @@ interface EmailStore {
    * grouped by the login and JMAP account they live in, then copied through
    * crossAccountMoveEmails with `keepOriginal`.
    */
-  copyEmailsToAccount: (emailIds: string[], destAccountId: string, destMailboxId: string) => Promise<void>;
+  /** Pass emails rather than ids where you have them: an id alone can name another account's namesake. */
+  copyEmailsToAccount: (emails: Array<string | Email>, destAccountId: string, destMailboxId: string) => Promise<void>;
   searchEmails: (client: IJMAPClient, query: string) => Promise<void>;
   advancedSearch: (client: IJMAPClient) => Promise<void>;
   setSearchFilters: (filters: Partial<SearchFilters>) => void;
@@ -1822,7 +1845,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   },
   selectEmail: (email) => {
     const prev = get().selectedEmail;
-    set({ selectedEmail: email, lastSelectedEmailKey: email?.id ?? get().lastSelectedEmailKey });
+    set({ selectedEmail: email, lastSelectedEmailKey: email ? emailKeyFor(email) : get().lastSelectedEmailKey });
     if (prev && (!email || email.id !== prev.id)) {
       emailHooks.onEmailClose.emitSync(prev);
     }
@@ -3149,8 +3172,9 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     // One group per (login, JMAP account): crossAccountMoveEmails takes a
     // single source JMAP account per call.
     const groups = new Map<string, { login: string; jmapAccountId?: string; ids: string[] }>();
-    for (const id of emailIds) {
-      const email = state.emails.find((e) => e.id === id)
+    for (const entry of emailIds) {
+      const id = typeof entry === 'string' ? entry : entry.id;
+      const email = typeof entry !== 'string' ? entry : state.emails.find((e) => e.id === id)
         ?? (state.selectedEmail?.id === id ? state.selectedEmail : undefined);
       // Aggregate views stamp each email with the login that reaches it and
       // its owning JMAP account; otherwise it lives in the open folder.
@@ -3634,7 +3658,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     // exactly those emails, never the keys and never a lookup by id (which
     // is what let a namesake in another account ride along). A targeted call
     // names its messages, and the account they belong to, itself.
-    const selectedEmails = target ? [] : emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
+    const selectedEmails = target ? [] : resolveSelectedEmails(get());
     const targetIds = target ? new Set(target.emailIds) : null;
     const emailIdsArray = targetIds ? Array.from(targetIds) : selectedEmails.map(e => e.id);
     if (emailIdsArray.length === 0) return;
@@ -3731,7 +3755,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   },
 
   batchSetTag: async (client, tagId, add) => {
-    const { selectedEmailKeys, emails } = get();
+    const { selectedEmailKeys } = get();
     if (selectedEmailKeys.size === 0) return;
 
     // Both prefixes name the same tag when read, so taking one off clears
@@ -3745,8 +3769,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     // folder's owner in a shared folder. (#281) The selection is keyed by
     // owning account, so a namesake in another account is never written.
     const groups = new Map<IJMAPClient, Map<string | undefined, Email[]>>();
-    for (const email of emails) {
-      if (!selectedEmailKeys.has(emailKeyFor(email))) continue;
+    for (const email of resolveSelectedEmails(get())) {
       // A message already in the wanted state needs no write.
       if (tagKeys.some(key => email.keywords?.[key] === true) === add) continue;
       const { client: actionClient, accountId } = resolveEmailActionContext(email, client);
@@ -3797,8 +3820,11 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       // The selection is keyed by owning account; JMAP takes the bare ids of
       // exactly those emails, never the keys and never a lookup by id (which
       // is what let a namesake in another account ride along).
-      const selectedEmails = emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
-      const emailIdsArray = selectedEmails.map(e => e.id);
+      const selectedEmails = resolveSelectedEmails(get());
+      if (selectedEmails.length === 0) {
+        set({ selectedEmailKeys: new Set(), isLoading: false });
+        return;
+      }
 
       // Determine if the current folder forces permanent deletion.
       const currentMailbox = mailboxes.find(m => m.id === selectedMailbox);
@@ -3813,12 +3839,14 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       // `sourceClientAccountId` and routes JMAP via `sourceAccountId`. Undecorated
       // emails (normal single-mailbox view) fall into '__default__' = active client.
       const accountMailboxes = get().accountMailboxes;
-      const bySource = new Map<string, { clientAccountId?: string; ids: string[] }>();
-      for (const emailId of emailIdsArray) {
-        const email = emails.find(e => e.id === emailId);
-        const key = email?.sourceAccountId || '__default__';
-        if (!bySource.has(key)) bySource.set(key, { clientAccountId: email?.sourceClientAccountId, ids: [] });
-        bySource.get(key)!.ids.push(emailId);
+      // Group the selected emails themselves: looking an id up in the list
+      // would find the first account's namesake and act on it instead.
+      const bySource = new Map<string, { clientAccountId?: string; ids: string[]; keys: string[] }>();
+      for (const email of selectedEmails) {
+        const key = email.sourceAccountId || '__default__';
+        if (!bySource.has(key)) bySource.set(key, { clientAccountId: email.sourceClientAccountId, ids: [], keys: [] });
+        bySource.get(key)!.ids.push(email.id);
+        bySource.get(key)!.keys.push(emailKeyFor(email));
       }
 
       // Undecorated emails viewed in a shared/group folder directly (non-unified)
@@ -3847,8 +3875,9 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       } else {
         // Move to trash per account.
         const failedAccounts: string[] = [];
-        const movedEmailIds = new Set<string>();
-        const promises = Array.from(bySource.entries()).map(async ([sourceAccountId, { clientAccountId, ids }]) => {
+        // Keys, not ids: a namesake in an account that failed must stay.
+        const movedKeys = new Set<string>();
+        const promises = Array.from(bySource.entries()).map(async ([sourceAccountId, { clientAccountId, ids, keys }]) => {
           const acctClient = getClient(sourceAccountId, clientAccountId);
           if (!acctClient) {
             failedAccounts.push(sourceAccountId);
@@ -3865,19 +3894,19 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
           }
           const trashId = trashMailbox.originalId || trashMailbox.id;
           await acctClient.batchMoveEmails(ids, trashId, jmapIdFor(sourceAccountId), alsoMarkRead);
-          ids.forEach(id => movedEmailIds.add(id));
+          keys.forEach(key => movedKeys.add(key));
         });
         await Promise.allSettled(promises);
 
-        if (failedAccounts.length > 0 && movedEmailIds.size === 0) {
+        if (failedAccounts.length > 0 && movedKeys.size === 0) {
           // Nothing moved - bail out so the UI doesn't drop the emails from view.
           throw new Error('Trash mailbox not found - cannot move emails to trash');
         }
 
         // Only remove successfully moved emails from local state.
-        if (movedEmailIds.size < emailIdsArray.length) {
-          const deletedEmails = emails.filter(e => movedEmailIds.has(e.id));
-          const remainingEmails = emails.filter(e => !movedEmailIds.has(e.id));
+        if (movedKeys.size < selectedEmails.length) {
+          const deletedEmails = emails.filter(e => movedKeys.has(emailKeyFor(e)));
+          const remainingEmails = emails.filter(e => !movedKeys.has(emailKeyFor(e)));
           const mailboxPatch = applyBatchMailboxCounterUpdate(get(), deletedEmails, applyDeleteCounters);
           set({
             emails: remainingEmails,
@@ -3916,7 +3945,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
   batchMoveToMailbox: async (client, toMailboxId, target) => {
     const { selectedEmailKeys, emails } = get();
     // Keyed selection as in batchMarkAsRead; a targeted call names its own.
-    const selectedEmails = target ? [] : emails.filter(e => selectedEmailKeys.has(emailKeyFor(e)));
+    const selectedEmails = target ? [] : resolveSelectedEmails(get());
     const targetIds = target ? new Set(target.emailIds) : null;
     const emailIdsArray = targetIds ? Array.from(targetIds) : selectedEmails.map(e => e.id);
     if (emailIdsArray.length === 0) return;

From 1421e29a6d9b0b9c81d1d1fd809f7b0f6feede13 Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Sat, 10 Oct 2026 22:05:41 +0200
Subject: [PATCH 23/23] fix: toggle the focused conversation by key under
 Mountain View #1061

The x shortcut passed the bare email id, which the key-based selection
no longer accepts. It now passes the email, so the toggle hits the
right account's row in unified views.
---
 components/mail/mail-app.tsx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index a742c738f..c337be6be 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -909,7 +909,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
     // expansion.
     onToggleSelection: () => {
       if (isScheduledView || !selectedEmail) return;
-      toggleEmailSelection(selectedEmail.id);
+      toggleEmailSelection(selectedEmail);
     },
     // Mountain View's `g` sequences. `g s` goes to the "All starred" view when
     // the user has one - a list you arrive at and leave, like the other `g`