From b2931ced3ed784204d9d6d15196111a5eea23e7c Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Tue, 3 Nov 2026 10:44:02 +0100
Subject: [PATCH] feat: bring desktop windows back at the next start, open
 pop-outs from a warm spare and ask natively before discarding a draft

---
 app/(main)/[locale]/popout/spare/page.tsx     |   7 ++
 .../__tests__/composer-close-guard.test.tsx   |  35 +++++-
 components/email/email-composer.tsx           |  41 ++++++-
 .../__tests__/popout-compose-app.test.tsx     |  45 ++++++++
 components/popout/popout-compose-app.tsx      |  64 ++++++++++-
 components/popout/popout-spare-app.tsx        |  45 ++++++++
 .../settings/desktop-window-settings.tsx      |  26 +++++
 components/settings/general-settings.tsx      |   2 +
 lib/desktop/preferences.ts                    |  71 +++++++++++++
 lib/desktop/types.ts                          | 100 +++++++++++++++++-
 lib/desktop/window-restore.ts                 |  40 +++++++
 lib/draft-composer-data.ts                    |  60 +++++++++++
 lib/popout/open.ts                            |   6 ++
 lib/popout/window-role.ts                     |  10 +-
 locales/ar/common.json                        |  15 +++
 locales/ca/common.json                        |  15 +++
 locales/cs/common.json                        |  15 +++
 locales/da/common.json                        |  15 +++
 locales/de/common.json                        |  15 +++
 locales/en/common.json                        |  15 +++
 locales/es/common.json                        |  15 +++
 locales/et/common.json                        |  15 +++
 locales/fa/common.json                        |  15 +++
 locales/fr/common.json                        |  15 +++
 locales/he/common.json                        |  15 +++
 locales/hu/common.json                        |  15 +++
 locales/it/common.json                        |  15 +++
 locales/ja/common.json                        |  15 +++
 locales/ko/common.json                        |  15 +++
 locales/lv/common.json                        |  15 +++
 locales/mn/common.json                        |  15 +++
 locales/nb/common.json                        |  15 +++
 locales/nl/common.json                        |  15 +++
 locales/pl/common.json                        |  15 +++
 locales/pt/common.json                        |  15 +++
 locales/ro/common.json                        |  15 +++
 locales/ru/common.json                        |  15 +++
 locales/sk/common.json                        |  15 +++
 locales/th/common.json                        |  15 +++
 locales/tr/common.json                        |  15 +++
 locales/uk/common.json                        |  15 +++
 locales/vi/common.json                        |  15 +++
 locales/zh-TW/common.json                     |  15 +++
 locales/zh/common.json                        |  15 +++
 44 files changed, 987 insertions(+), 15 deletions(-)
 create mode 100644 app/(main)/[locale]/popout/spare/page.tsx
 create mode 100644 components/popout/popout-spare-app.tsx
 create mode 100644 components/settings/desktop-window-settings.tsx
 create mode 100644 lib/desktop/preferences.ts
 create mode 100644 lib/desktop/window-restore.ts
 create mode 100644 lib/draft-composer-data.ts

diff --git a/app/(main)/[locale]/popout/spare/page.tsx b/app/(main)/[locale]/popout/spare/page.tsx
new file mode 100644
index 000000000..1eafe6639
--- /dev/null
+++ b/app/(main)/[locale]/popout/spare/page.tsx
@@ -0,0 +1,7 @@
+import { PopoutSpareApp } from "@/components/popout/popout-spare-app";
+
+// The desktop app's warm spare (components/popout/popout-spare-app.tsx). Not in
+// Lite: scripts/lite removes this tree.
+export default function PopoutSparePage() {
+  return <PopoutSpareApp />;
+}
diff --git a/components/email/__tests__/composer-close-guard.test.tsx b/components/email/__tests__/composer-close-guard.test.tsx
index 8ac5e5b82..9ef9370a7 100644
--- a/components/email/__tests__/composer-close-guard.test.tsx
+++ b/components/email/__tests__/composer-close-guard.test.tsx
@@ -1,5 +1,5 @@
 import { render, screen, fireEvent, waitFor, act, within } from '@testing-library/react';
-import { beforeEach, describe, it, expect, vi } from 'vitest';
+import { afterEach, beforeEach, describe, it, expect, vi } from 'vitest';
 import React from 'react';
 import { EmailComposer } from '../email-composer';
 import { useAuthStore } from '@/stores/auth-store';
@@ -235,6 +235,39 @@ describe('composer close guard with a follow-up', () => {
     expect(afterClose).not.toHaveBeenCalled();
   });
 
+  describe('in the desktop app', () => {
+    afterEach(() => {
+      window.bulwarkDesktop = undefined;
+    });
+
+    const nativeBridge = (answer: number) => {
+      const confirm = vi.fn(async () => answer);
+      window.bulwarkDesktop = { version: 1, platform: 'win32', dialogs: { confirm } } as never;
+      return confirm;
+    };
+
+    it('asks through the OS, and shows no dialog of its own', async () => {
+      const confirm = nativeBridge(2);
+      const { requestCloseRef, afterClose, onClose } = renderWithCloseRef();
+      act(() => requestCloseRef.current!(afterClose));
+      await waitFor(() => expect(confirm).toHaveBeenCalledTimes(1));
+      expect(confirm.mock.calls[0]).toMatchObject([{ message: 'close_draft_title', buttons: ['save', 'discard', 'cancel'], defaultId: 0 }]);
+      expect(screen.queryByText('close_draft_title')).not.toBeInTheDocument();
+      // The last button is Cancel: nothing happens.
+      await act(async () => {});
+      expect(onClose).not.toHaveBeenCalled();
+      expect(afterClose).not.toHaveBeenCalled();
+    });
+
+    it('Discard discards, and the follow-up runs', async () => {
+      nativeBridge(1);
+      const { requestCloseRef, afterClose, onClose } = renderWithCloseRef();
+      act(() => requestCloseRef.current!(afterClose));
+      await waitFor(() => expect(onClose).toHaveBeenCalledTimes(1));
+      await waitFor(() => expect(afterClose).toHaveBeenCalledTimes(1));
+    });
+  });
+
   it('runs the follow-up after discarding', async () => {
     const { requestCloseRef, afterClose, onClose } = renderWithCloseRef();
 
diff --git a/components/email/email-composer.tsx b/components/email/email-composer.tsx
index d4ff3a9a8..2e25fdb4d 100644
--- a/components/email/email-composer.tsx
+++ b/components/email/email-composer.tsx
@@ -166,6 +166,8 @@ import { htmlToPlainText as htmlToPlainTextShared } from "@/lib/html-to-text";
 import { fileStorage } from "@/lib/plugin-storage";
 import { usePolicyStore } from "@/stores/policy-store";
 import { registerComposeFlush } from "@/lib/compose-flush-registry";
+import { getDesktopBridge } from "@/lib/desktop/bridge";
+import { noteOpenDraft } from "@/lib/desktop/window-restore";
 import type { RescuedDraft } from "@/lib/popout/channel";
 import { toUnicodeEmail } from "@/lib/idn";
 
@@ -1936,6 +1938,14 @@ export function EmailComposer({
   // eslint-disable-next-line react-hooks/exhaustive-deps
   }, []);
 
+  // A composer that comes back with the app: a draft it opened on counts from the start.
+  // Gone with the composer: sent, discarded or closed.
+  useEffect(() => {
+    if (draftIdRef.current) noteOpenDraft(effectiveSessionKey, { draftId: draftIdRef.current, localAccountId: draftLocalAccountIdRef.current, ownerAccountId: draftAccountIdRef.current });
+    return () => noteOpenDraft(effectiveSessionKey, null);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [effectiveSessionKey]);
+
   // Auto-save draft to server on page close (best-effort)
   const ownWindowRef = useRef(ownWindow);
   ownWindowRef.current = ownWindow;
@@ -3005,6 +3015,8 @@ export function EmailComposer({
       draftIdRef.current = savedDraftId;
       draftAccountIdRef.current = draftAccountId;
       draftLocalAccountIdRef.current = savingLogin;
+      // Before a save's promise settles: quitting waits for it, then keeps this list.
+      noteOpenDraft(effectiveSessionKey, { draftId: savedDraftId, localAccountId: savingLogin, ownerAccountId: draftAccountId });
       setDraftId(savedDraftId);
       setDraftAccountId(draftAccountId);
       setDraftLocalAccountId(savingLogin);
@@ -4418,6 +4430,29 @@ export function EmailComposer({
     emitClose();
   };
 
+  /** The question before closing or discarding: the OS's own in the desktop app. */
+  const openCloseDialog = (kind: 'discard' | 'close') => {
+    const dialogs = getDesktopBridge()?.dialogs;
+    if (!dialogs) {
+      setCloseDialogKind(kind);
+      setShowCloseDialog(true);
+      return;
+    }
+    const discarding = kind === 'discard';
+    const buttons = discarding ? [t('discard'), t('cancel')] : [tCommon('save'), t('discard'), t('cancel')];
+    void dialogs.confirm({
+      type: 'warning',
+      message: discarding ? t('discard_draft_title') : t('close_draft_title'),
+      detail: discarding ? t('discard_draft_message') : t('close_draft_message'),
+      buttons,
+      defaultId: discarding ? 1 : 0,
+    }).then((choice) => {
+      if (buttons[choice] === t('discard')) handleDiscardAndClose();
+      else if (!discarding && choice === 0) void handleSaveDraftAndClose();
+      else afterCloseRef.current = null;
+    });
+  };
+
   // Discard deletes the draft, also one that has no unsaved changes, such as
   // a scheduled message reopened with "Cancel and edit". It used to share the
   // X button's path, which closed such a composer and kept the draft.
@@ -4429,8 +4464,7 @@ export function EmailComposer({
       return;
     }
     afterCloseRef.current = null;
-    setCloseDialogKind('discard');
-    setShowCloseDialog(true);
+    openCloseDialog('discard');
   };
 
   const handleClose = (afterClose?: () => void) => {
@@ -4442,8 +4476,7 @@ export function EmailComposer({
       && !saveFailedRef.current
       && !attachmentsRef.current.some(att => att.uploading || att.error);
     if (isDirtyRef.current && !savedAlready) {
-      setCloseDialogKind('close');
-      setShowCloseDialog(true);
+      openCloseDialog('close');
     } else {
       cleanClose();
     }
diff --git a/components/popout/__tests__/popout-compose-app.test.tsx b/components/popout/__tests__/popout-compose-app.test.tsx
index 3ff5cf883..2a02faf0f 100644
--- a/components/popout/__tests__/popout-compose-app.test.tsx
+++ b/components/popout/__tests__/popout-compose-app.test.tsx
@@ -67,6 +67,51 @@ function openAt(handoffId: string) {
   render(<PopoutComposeApp />);
 }
 
+describe('a composer coming back on its draft', () => {
+  const closeSelf = vi.fn();
+
+  beforeEach(() => {
+    closeSelf.mockClear();
+    window.bulwarkDesktop = { version: 1, platform: 'win32', windows: { closeSelf } } as never;
+  });
+
+  afterEach(() => {
+    window.bulwarkDesktop = undefined;
+  });
+
+  const draft = {
+    id: 'd1', subject: 'Half-written', to: [{ email: 'a@example.org' }], cc: [], bcc: [], from: [{ email: 'me@example.org' }],
+    bodyValues: { t: { value: 'Text' } }, textBody: [{ partId: 't', type: 'text/plain' }], htmlBody: [], attachments: [{ blobId: 'b1', name: 'a.pdf', type: 'application/pdf', size: 3 }],
+  };
+
+  const openDraft = (getEmail: ReturnType<typeof vi.fn>, search = 'draft=d1&account=alice&owner=group') => {
+    useAuthStore.setState({ client: { getEmail } as never, getClientForAccount: () => undefined } as never);
+    window.history.replaceState(null, '', `/en/popout/compose?${search}`);
+    render(<PopoutComposeApp />);
+  };
+
+  it('reads the draft from where it lives, and opens the composer on it, id and all', async () => {
+    const getEmail = vi.fn(async () => draft);
+    openDraft(getEmail);
+    await waitFor(() => expect(screen.getByTestId('composer').textContent).toBe('Half-written'));
+    expect(getEmail).toHaveBeenCalledWith('d1', 'group');
+    // Saving goes over this draft, not next to it, and its files stay.
+    expect(composer?.initialData).toMatchObject({ draftId: 'd1', draftAccountId: 'group', draftLocalAccountId: 'alice', to: 'a@example.org' });
+    expect((composer?.initialData as unknown as { attachments: unknown[] }).attachments).toHaveLength(1);
+  });
+
+  it('a draft that has gone since (sent elsewhere) closes the window', async () => {
+    openDraft(vi.fn(async () => null));
+    await waitFor(() => expect(closeSelf).toHaveBeenCalledTimes(1));
+    expect(screen.queryByTestId('composer')).toBeNull();
+  });
+
+  it('a server that doesn\'t answer closes it too: the draft is safe on the server', async () => {
+    openDraft(vi.fn(async () => { throw new Error('offline'); }));
+    await waitFor(() => expect(closeSelf).toHaveBeenCalledTimes(1));
+  });
+});
+
 describe('PopoutComposeApp', () => {
   it('tells the opening window to let go only with the composer on screen', async () => {
     const handoff = createComposeHandoff()!;
diff --git a/components/popout/popout-compose-app.tsx b/components/popout/popout-compose-app.tsx
index 6f0bebeff..7aaa4f709 100644
--- a/components/popout/popout-compose-app.tsx
+++ b/components/popout/popout-compose-app.tsx
@@ -18,6 +18,8 @@ import { announceMailChanged, announceSentToMainWindow, askRescuedDraftId, watch
 import { acknowledgeComposeHandoff, receiveComposeHandoff, rememberComposePayload, rememberedComposePayload, watchHandoffCancel } from "@/lib/popout/compose-handoff";
 import type { ComposePopoutPayload } from "@/lib/popout/compose-payload";
 import { closePopoutWindow } from "@/lib/popout/window-role";
+import { composerDataFromDraft } from "@/lib/draft-composer-data";
+import { useIdentityStore } from "@/stores/identity-store";
 import { PopoutShell, PopoutSkeleton } from "./popout-shell";
 
 /** A warning with no main window left to show it stays this long before the window goes. */
@@ -31,10 +33,60 @@ const EMPTY_PAYLOAD: ComposePopoutPayload = { mode: "compose" };
 /** How long a reloaded window waits to hear what became of the text it handed over on the way out. */
 const RESCUE_ANSWER_MS = 2000;
 
-function readLaunch(): { handoffId: string | null; accountId?: string } {
+function readLaunch(): { handoffId: string | null; accountId?: string; draftId?: string; ownerAccountId?: string } {
   if (typeof window === "undefined") return { handoffId: null };
   const search = new URLSearchParams(window.location.search);
-  return { handoffId: search.get("handoff"), accountId: search.get("account") ?? undefined };
+  return {
+    handoffId: search.get("handoff"),
+    accountId: search.get("account") ?? undefined,
+    draftId: search.get("draft") ?? undefined,
+    ownerAccountId: search.get("owner") ?? undefined,
+  };
+}
+
+/**
+ * The composer that was open when the desktop app quit, back on its draft. A draft
+ * that has gone since (sent or deleted elsewhere) means there's nothing to show.
+ */
+function RestoredDraft({ draftId, accountId, ownerAccountId, onReady }: {
+  draftId: string;
+  accountId?: string;
+  ownerAccountId?: string;
+  onReady: (payload: ComposePopoutPayload) => void;
+}) {
+  const t = useTranslations();
+  const tWindows = useTranslations("pwaWindows");
+  const client = useAuthStore((s) => (accountId ? s.getClientForAccount(accountId) : undefined) ?? s.client);
+  const identities = useIdentityStore((s) => s.identities);
+  useEffect(() => {
+    if (!client) return;
+    let cancelled = false;
+    void client.getEmail(draftId, ownerAccountId).then((draft) => {
+      if (cancelled) return;
+      if (!draft) {
+        closePopoutWindow();
+        return;
+      }
+      onReady({
+        mode: "compose",
+        initialData: composerDataFromDraft(draft, {
+          accountId: ownerAccountId,
+          localAccountId: accountId,
+          identities,
+          noSubject: t("email_composer.no_subject"),
+        }),
+      });
+    }).catch((error) => {
+      debug.error("Failed to reopen a draft:", error);
+      if (!cancelled) closePopoutWindow();
+    });
+    return () => {
+      cancelled = true;
+    };
+    // Once per client: the draft doesn't change under a window still opening.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [client, draftId, ownerAccountId]);
+  return <PopoutSkeleton label={tWindows("opening")} />;
 }
 
 /** The composer alone, in its own window: sending, autosave and discard go through the shared stores, as in a Pro tab. */
@@ -181,8 +233,8 @@ function PopoutComposer({ payload, handoffId }: { payload: ComposePopoutPayload;
 /** `/popout/compose`: a draft handed over by another window, or a new message. */
 export function PopoutComposeApp() {
   const t = useTranslations("pwaWindows");
-  const [{ handoffId, accountId }] = useState(readLaunch);
-  const [payload, setPayload] = useState<ComposePopoutPayload | null>(handoffId ? null : EMPTY_PAYLOAD);
+  const [{ handoffId, accountId, draftId, ownerAccountId }] = useState(readLaunch);
+  const [payload, setPayload] = useState<ComposePopoutPayload | null>(handoffId || draftId ? null : EMPTY_PAYLOAD);
 
   useEffect(() => {
     if (!handoffId) return;
@@ -216,7 +268,9 @@ export function PopoutComposeApp() {
 
   return (
     <PopoutShell kind="compose" accountId={accountId}>
-      {payload ? <PopoutComposer payload={payload} handoffId={handoffId} /> : <PopoutSkeleton label={t("opening")} />}
+      {payload ? <PopoutComposer payload={payload} handoffId={handoffId} />
+        : draftId ? <RestoredDraft draftId={draftId} accountId={accountId} ownerAccountId={ownerAccountId} onReady={setPayload} />
+        : <PopoutSkeleton label={t("opening")} />}
     </PopoutShell>
   );
 }
diff --git a/components/popout/popout-spare-app.tsx b/components/popout/popout-spare-app.tsx
new file mode 100644
index 000000000..26f67104e
--- /dev/null
+++ b/components/popout/popout-spare-app.tsx
@@ -0,0 +1,45 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { getDesktopBridge } from "@/lib/desktop/bridge";
+import { withBasePath } from "@/lib/browser-navigation";
+import { PopoutComposeApp } from "./popout-compose-app";
+import { PopoutMessageApp } from "./popout-message-app";
+
+/** The message id a pop-out address names. */
+function messageIdOf(pathname: string): string {
+  const segments = pathname.split("/").filter(Boolean);
+  const at = segments.lastIndexOf("message");
+  return at >= 0 && segments[at + 1] ? decodeURIComponent(segments[at + 1]) : "";
+}
+
+/**
+ * The desktop app's warm spare: a hidden window with the pop-out code loaded and
+ * nothing signed in. When a pop-out is wanted the shell gives it an address. The
+ * address bar changes without a load, which is where the pop-outs read their
+ * arguments from, and the right one renders in a window that's already up.
+ */
+export function PopoutSpareApp() {
+  const [target, setTarget] = useState<URL | null>(null);
+
+  useEffect(() => {
+    const spare = getDesktopBridge()?.windows?.spare;
+    if (!spare) {
+      // Someone typed the address, or a browser followed a link.
+      window.location.replace(withBasePath("/"));
+      return;
+    }
+    const stop = spare.onActivate((url) => {
+      const next = new URL(url, window.location.href);
+      window.history.replaceState(null, "", `${next.pathname}${next.search}`);
+      setTarget(next);
+      spare.taken();
+    });
+    spare.ready();
+    return stop;
+  }, []);
+
+  if (!target) return <div data-popout-spare="" className="h-dvh bg-background" />;
+  if (/\/popout\/compose\/?$/.test(target.pathname)) return <PopoutComposeApp />;
+  return <PopoutMessageApp id={messageIdOf(target.pathname)} />;
+}
diff --git a/components/settings/desktop-window-settings.tsx b/components/settings/desktop-window-settings.tsx
new file mode 100644
index 000000000..3d604728c
--- /dev/null
+++ b/components/settings/desktop-window-settings.tsx
@@ -0,0 +1,26 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useTranslations } from "next-intl";
+import { hasDesktopWindows } from "@/lib/popout/support";
+import { setDesktopPref, useDesktopPrefs } from "@/lib/desktop/preferences";
+import { SettingItem, SettingsSection, ToggleSwitch } from "./settings-section";
+
+/** How the desktop app's windows behave. Only there: a browser has nothing to set. */
+export function DesktopWindowSettings() {
+  const t = useTranslations("desktopUi.settings");
+  const prefs = useDesktopPrefs();
+  const [shown, setShown] = useState(false);
+  useEffect(() => setShown(hasDesktopWindows()), []);
+  if (!shown) return null;
+  return (
+    <SettingsSection id="desktop-windows" title={t("title")}>
+      <SettingItem label={t("double_click_label")} description={t("double_click_description")}>
+        <ToggleSwitch checked={prefs.openOnDoubleClick} onChange={(checked) => setDesktopPref("openOnDoubleClick", checked)} />
+      </SettingItem>
+      <SettingItem label={t("restore_label")} description={t("restore_description")}>
+        <ToggleSwitch checked={prefs.restoreWindows} onChange={(checked) => setDesktopPref("restoreWindows", checked)} />
+      </SettingItem>
+    </SettingsSection>
+  );
+}
diff --git a/components/settings/general-settings.tsx b/components/settings/general-settings.tsx
index 41d2ba072..7dc969209 100644
--- a/components/settings/general-settings.tsx
+++ b/components/settings/general-settings.tsx
@@ -9,6 +9,7 @@ import { useTour } from '@/components/tour/tour-provider';
 import { Button } from '@/components/ui/button';
 import { PlayCircle } from '@/components/icons';
 import { IS_LITE } from '@/lib/lite';
+import { DesktopWindowSettings } from './desktop-window-settings';
 
 /**
  * The General page: language and time, which links the browser hands to
@@ -26,6 +27,7 @@ export function GeneralSettings({ supportsCalendar }: { supportsCalendar: boolea
 
       {!IS_LITE && <ProtocolHandlerSettings supportsCalendar={supportsCalendar} />}
 
+      <DesktopWindowSettings />
       <SettingsSection id="tour" title={tTour('settings_section')}>
         <SettingItem label={tTour('restart_title')} description={tTour('restart_desc')}>
           <Button
diff --git a/lib/desktop/preferences.ts b/lib/desktop/preferences.ts
new file mode 100644
index 000000000..f9894c5c8
--- /dev/null
+++ b/lib/desktop/preferences.ts
@@ -0,0 +1,71 @@
+/**
+ * What the desktop app's windows do. These belong to this computer, not the account
+ * (one user can have a laptop and a desktop that differ), so they stay out of the
+ * synced settings. The shell gets its copy of "restore" from the host.
+ */
+
+import { useSyncExternalStore } from 'react';
+
+const STORAGE_KEY = 'bulwark-desktop-window-prefs';
+
+export interface DesktopWindowPrefs {
+  /** Double-clicking a message opens it in its own window. */
+  openOnDoubleClick: boolean;
+  /** The windows open at quit come back at the next start. */
+  restoreWindows: boolean;
+}
+
+const DEFAULTS: DesktopWindowPrefs = { openOnDoubleClick: true, restoreWindows: true };
+
+let cached: DesktopWindowPrefs | null = null;
+const listeners = new Set<() => void>();
+
+export function readDesktopPrefs(): DesktopWindowPrefs {
+  if (cached) return cached;
+  let stored: Partial<DesktopWindowPrefs> = {};
+  try {
+    const raw = typeof localStorage === 'undefined' ? null : localStorage.getItem(STORAGE_KEY);
+    if (raw) stored = JSON.parse(raw) as Partial<DesktopWindowPrefs>;
+  } catch {
+    // Damaged: the defaults.
+  }
+  cached = {
+    openOnDoubleClick: typeof stored.openOnDoubleClick === 'boolean' ? stored.openOnDoubleClick : DEFAULTS.openOnDoubleClick,
+    restoreWindows: typeof stored.restoreWindows === 'boolean' ? stored.restoreWindows : DEFAULTS.restoreWindows,
+  };
+  return cached;
+}
+
+export function setDesktopPref<K extends keyof DesktopWindowPrefs>(key: K, value: DesktopWindowPrefs[K]): void {
+  cached = { ...readDesktopPrefs(), [key]: value };
+  try {
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(cached));
+  } catch {
+    // Full or unavailable: it holds until the window closes.
+  }
+  for (const listener of [...listeners]) listener();
+}
+
+function subscribe(listener: () => void): () => void {
+  listeners.add(listener);
+  // Another window changed it.
+  const onStorage = (event: StorageEvent) => {
+    if (event.key !== STORAGE_KEY) return;
+    cached = null;
+    listener();
+  };
+  window.addEventListener('storage', onStorage);
+  return () => {
+    listeners.delete(listener);
+    window.removeEventListener('storage', onStorage);
+  };
+}
+
+export function useDesktopPrefs(): DesktopWindowPrefs {
+  return useSyncExternalStore(subscribe, readDesktopPrefs, () => DEFAULTS);
+}
+
+/** Test helper. */
+export function resetDesktopPrefsCache(): void {
+  cached = null;
+}
diff --git a/lib/desktop/types.ts b/lib/desktop/types.ts
index e049b727b..1a4245c63 100644
--- a/lib/desktop/types.ts
+++ b/lib/desktop/types.ts
@@ -16,6 +16,8 @@ export interface DesktopWindowInfo {
   type: DesktopWindowType;
   title: string;
   focused: boolean;
+  /** False for a main window hidden while pop-outs are open. */
+  visible?: boolean;
 }
 
 export interface DesktopWindowsBridge {
@@ -34,13 +36,72 @@ export interface DesktopWindowsBridge {
   list?: () => Promise<DesktopWindowInfo[]>;
   /** Fires when a window opens, closes, retitles or takes the focus. Returns the unsubscribe. */
   onChanged?: (listener: (windows: DesktopWindowInfo[]) => void) => () => void;
+  /**
+   * This page has saved or discarded and closes its window. Goes through the shell
+   * so bounds get stored and no second save runs. Works however the window opened.
+   */
+  closeSelf?: () => void;
+  /** What this window's open drafts come back as at the next start: pop-out composer addresses. */
+  setRestore?: (urls: string[]) => void;
+  setRestoreEnabled?: (enabled: boolean) => void;
+  /** Signed in, with a session to lend: windows from last time can open. */
+  sessionReady?: () => void;
+  /** The warm spare's page, see components/popout/popout-spare-app.tsx. */
+  spare?: {
+    ready: () => void;
+    taken: () => void;
+    onActivate: (listener: (url: string) => void) => () => void;
+  };
 }
 
 export interface DesktopThemeBridge {
   /** The page's colours, for title bar buttons and the first frame of new windows. */
   set: (theme: { dark: boolean; background: string; foreground?: string }) => void;
-  /** Fires when the OS switches between light and dark. Returns the unsubscribe. */
-  onSystemChange?: (listener: (system: { dark: boolean; highContrast: boolean }) => void) => () => void;
+  /** Fires when the OS switches between light and dark, contrast or accent. Returns the unsubscribe. */
+  onSystemChange?: (listener: (system: DesktopSystemTheme) => void) => () => void;
+  /** How the OS looks now. */
+  system?: () => Promise<DesktopSystemTheme>;
+}
+
+export interface DesktopSystemTheme {
+  dark: boolean;
+  highContrast: boolean;
+  /** The OS accent colour as #rrggbb, where the OS has one and tells. */
+  accent?: string;
+}
+
+export type DesktopMenuState = Record<string, boolean | { enabled?: boolean; checked?: boolean }>;
+
+/** A native menu built from an HTML one (lib/desktop/native-menu.ts). */
+export interface DesktopNativeMenuItem {
+  /** Handed back when this item is chosen. Left out of separators and submenus. */
+  id?: string;
+  label?: string;
+  type?: 'normal' | 'separator' | 'checkbox' | 'radio';
+  enabled?: boolean;
+  checked?: boolean;
+  submenu?: DesktopNativeMenuItem[];
+}
+
+export interface DesktopMenuBarEntry {
+  id: string;
+  label: string;
+  /** The letter that opens it with Alt, lower case. */
+  mnemonic?: string;
+}
+
+export interface DesktopMenuBarEvent {
+  visible: boolean;
+  /** Open this menu right away: Alt plus its letter. */
+  open?: string;
+}
+
+/** What a page answers when asked to save before a window goes. */
+export interface DesktopFlushAnswer {
+  failed?: number;
+  timedOut?: boolean;
+  /** Mail waiting to be sent. */
+  unsent?: number;
 }
 
 export interface DesktopMenuBridge {
@@ -48,12 +109,41 @@ export interface DesktopMenuBridge {
    * What the app menu shows as enabled or checked, by command id. The shell
    * keeps the last state per window and applies it when that window has focus.
    */
-  setState: (state: Record<string, boolean | { enabled?: boolean; checked?: boolean }>) => void;
+  setState: (state: DesktopMenuState) => void;
+  /** A menu command to run. Returns the unsubscribe. */
+  onCommand?: (listener: (id: string) => void) => () => void;
+  /** Shows a native menu. At the pointer when `at` is left out. Answers with the id picked, or null. */
+  popup?: (items: DesktopNativeMenuItem[], at?: { x: number; y: number }) => Promise<string | null>;
+  /** The strip that stands in for a menu bar in a window with no native bar. */
+  bar?: {
+    entries: () => Promise<DesktopMenuBarEntry[]>;
+    /** Opens that menu natively, at page coordinates. */
+    open: (id: string, at: { x: number; y: number }) => void;
+    onEvent: (listener: (event: DesktopMenuBarEvent) => void) => () => void;
+  };
 }
 
 export interface DesktopShellBridge {
   /** http, https and mailto only. */
   openExternal: (url: string) => void;
+  /** The shell's menus follow `ui`. Spellcheck follows both. */
+  setLanguages?: (languages: { ui: string; composer?: string[] }) => void;
+}
+
+export interface DesktopDialogsBridge {
+  /** A native question. Answers with the index of the button chosen. The last button is the safe one. */
+  confirm: (options: {
+    message: string;
+    detail?: string;
+    buttons: string[];
+    defaultId?: number;
+    type?: 'none' | 'info' | 'warning' | 'question';
+  }) => Promise<number>;
+}
+
+export interface DesktopClipboardBridge {
+  /** Puts a file on the clipboard, for pasting into a folder. False when that didn't work. */
+  copyFile: (name: string, data: ArrayBuffer) => Promise<boolean>;
 }
 
 export type DesktopServerPrepareResult =
@@ -83,7 +173,7 @@ export interface DesktopLifecycleBridge {
    * Before a window closes or the app quits, the shell asks the page to save what
    * it has and waits a few seconds. A window with no handler closes at once.
    */
-  onFlushRequest: (handler: () => Promise<unknown>) => () => void;
+  onFlushRequest: (handler: () => Promise<DesktopFlushAnswer | unknown>) => () => void;
 }
 
 export type DesktopBrowserSignInResult =
@@ -119,6 +209,8 @@ export interface BulwarkDesktopBridge {
   theme?: DesktopThemeBridge;
   menu?: DesktopMenuBridge;
   shell?: DesktopShellBridge;
+  dialogs?: DesktopDialogsBridge;
+  clipboard?: DesktopClipboardBridge;
   lifecycle?: DesktopLifecycleBridge;
   servers?: DesktopServersBridge;
   auth?: DesktopAuthBridge;
diff --git a/lib/desktop/window-restore.ts b/lib/desktop/window-restore.ts
new file mode 100644
index 000000000..d09ed7038
--- /dev/null
+++ b/lib/desktop/window-restore.ts
@@ -0,0 +1,40 @@
+/**
+ * What a composer comes back as when the app starts again: a pop-out on its draft.
+ * Each open composer says which draft it holds, as soon as it has one. The shell
+ * keeps the list per window. Closing a window drops its list, so a draft the user
+ * put away stays in Drafts and doesn't come back on screen. Quitting keeps it.
+ */
+
+import { appPath } from '@/lib/deep-links';
+import { getDesktopBridge } from './bridge';
+
+export interface OpenDraft {
+  draftId: string;
+  /** The login it was saved through. */
+  localAccountId?: string | null;
+  /** The JMAP account holding it, when not that login's own. */
+  ownerAccountId?: string | null;
+}
+
+const open = new Map<string, OpenDraft>();
+
+export function restoreUrlFor(draft: OpenDraft): string {
+  const search = new URLSearchParams({ draft: draft.draftId });
+  if (draft.localAccountId) search.set('account', draft.localAccountId);
+  if (draft.ownerAccountId) search.set('owner', draft.ownerAccountId);
+  return `${appPath('/popout/compose')}?${search.toString()}`;
+}
+
+/** With null, this composer holds no draft any more: sent, discarded or closed. */
+export function noteOpenDraft(key: string, draft: OpenDraft | null): void {
+  const windows = getDesktopBridge()?.windows;
+  if (!windows?.setRestore) return;
+  if (draft) open.set(key, draft);
+  else if (!open.delete(key)) return;
+  windows.setRestore([...open.values()].map(restoreUrlFor));
+}
+
+/** Test helper. */
+export function resetOpenDrafts(): void {
+  open.clear();
+}
diff --git a/lib/draft-composer-data.ts b/lib/draft-composer-data.ts
new file mode 100644
index 000000000..82eebc52d
--- /dev/null
+++ b/lib/draft-composer-data.ts
@@ -0,0 +1,60 @@
+import type { ComposerDraftData } from '@/components/email/email-composer';
+import { findDraftIdentityIdForLogin, type DraftSource } from '@/lib/draft-source';
+import { getDraftComposerBody } from '@/lib/email-body-selection';
+import type { Email, Identity } from '@/lib/jmap/types';
+import { messagePriorityFromHeaders } from '@/lib/message-priority';
+import { reopenedLabelChoice } from '@/lib/outgoing/classification';
+
+/**
+ * What a composer starts from when a saved draft is opened: from the list, or from
+ * last time the desktop app was running. `draft` has its full body.
+ */
+export function composerDataFromDraft(
+  draft: Email,
+  { accountId, localAccountId, identities, noSubject }: DraftSource & { identities: Identity[]; noSubject: string },
+): ComposerDraftData {
+  const { body, plainTextMode } = getDraftComposerBody(draft);
+  return {
+    to: draft.to?.map((a) => a.email).filter(Boolean).join(', ') || '',
+    cc: draft.cc?.map((a) => a.email).filter(Boolean).join(', ') || '',
+    bcc: draft.bcc?.map((a) => a.email).filter(Boolean).join(', ') || '',
+    // Drafts saved before #1189 stored an empty subject as the composer's
+    // "(No Subject)" placeholder; reopen those with an empty field.
+    subject: draft.subject && draft.subject !== noSubject ? draft.subject : '',
+    body,
+    // Re-open in the format the draft was written in (#1022).
+    plainTextMode,
+    showCc: (draft.cc?.length || 0) > 0,
+    showBcc: (draft.bcc?.length || 0) > 0,
+    // Restore the identity the draft was composed with: the saved From (name and
+    // address) against the list the composer renders, so a draft from a non-active
+    // account, or one of two identities sharing an address, isn't reset to the default.
+    selectedIdentityId: findDraftIdentityIdForLogin(identities, draft.from?.[0], localAccountId),
+    subAddressTag: '',
+    mode: 'compose',
+    draftId: draft.id,
+    draftAccountId: accountId,
+    draftLocalAccountId: localAccountId,
+    // A reply draft re-opens in compose mode; its threading headers must
+    // come along or the reply leaves its thread.
+    inReplyTo: draft.inReplyTo ?? undefined,
+    references: draft.references ?? undefined,
+    priority: messagePriorityFromHeaders(draft.headers),
+    // A sent message brought back (Undo, Cancel and edit) has no draft
+    // marker: its SIO-Label says which label it went out with.
+    classification: reopenedLabelChoice(draft.headers, localAccountId),
+    // Existing server-side attachments must ride along, or the composer
+    // starts empty and the next save/send silently rebuilds the draft
+    // without them (#849).
+    attachments: (draft.attachments ?? [])
+      .filter((a) => !!a.blobId)
+      .map((a) => ({
+        blobId: a.blobId,
+        name: a.name,
+        type: a.type,
+        size: a.size,
+        cid: a.cid,
+        disposition: a.disposition,
+      })),
+  };
+}
diff --git a/lib/popout/open.ts b/lib/popout/open.ts
index e1d51ea37..3cee94b3d 100644
--- a/lib/popout/open.ts
+++ b/lib/popout/open.ts
@@ -75,6 +75,12 @@ export function openMessageWindow(target: MessageWindowTarget): boolean {
   return focused(openWindow(messagePopoutUrl(target), `bulwark-message-${target.emailId.replace(/\W/g, '_')}`, 'message'));
 }
 
+/** A new message in its own window, with nothing to hand over. */
+export function openNewComposerWindow(localAccountId?: string | null): boolean {
+  const name = `bulwark-compose-new-${Date.now().toString(36)}`;
+  return focused(openWindow(appPath('/popout/compose') + query({ account: localAccountId }), name, 'compose'));
+}
+
 export interface ComposerWindow {
   /** Hands the draft over. True once the composer is on screen there; until then the sender keeps its copy. */
   handOver(payload: ComposePopoutPayload): Promise<boolean>;
diff --git a/lib/popout/window-role.ts b/lib/popout/window-role.ts
index de20ee6cf..3b1efe642 100644
--- a/lib/popout/window-role.ts
+++ b/lib/popout/window-role.ts
@@ -7,6 +7,7 @@
  * stores/auth-store.ts and stores/account-store.ts ask here.
  */
 
+import { getDesktopBridge } from '@/lib/desktop/bridge';
 import { withBasePath } from '@/lib/browser-navigation';
 import { locales } from '@/i18n/routing';
 
@@ -28,7 +29,7 @@ export function isPopoutPath(pathname: string): boolean {
   if (before.length > 0 && !(locales as readonly string[]).includes(before[before.length - 1])) return false;
   if (before.some((segment) => OTHER_SECTIONS.has(segment))) return false;
   const rest = segments.slice(at + 1);
-  return (rest.length === 1 && rest[0] === 'compose') || (rest.length === 2 && rest[0] === 'message');
+  return (rest.length === 1 && (rest[0] === 'compose' || rest[0] === 'spare')) || (rest.length === 2 && rest[0] === 'message');
 }
 
 export function isPopoutWindow(): boolean {
@@ -61,6 +62,13 @@ export function mainWindowStorage(): Pick<Storage, 'getItem' | 'setItem' | 'remo
  */
 export function closePopoutWindow(): void {
   if (typeof window === 'undefined') return;
+  // The desktop app closes it for us: however the window came to be, and past the
+  // shell's own bookkeeping. Whoever calls this has saved or discarded by now.
+  const closeSelf = getDesktopBridge()?.windows?.closeSelf;
+  if (closeSelf) {
+    closeSelf();
+    return;
+  }
   window.close();
   window.setTimeout(() => {
     if (!window.closed) window.location.replace(withBasePath('/'));
diff --git a/locales/ar/common.json b/locales/ar/common.json
index 91db0f8ea..70b78099f 100644
--- a/locales/ar/common.json
+++ b/locales/ar/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "تم نقل هذه الرسالة إلى {folder}.",
     "window_not_ready": "لم تفتح النافذة الجديدة في الوقت المناسب. تبقى مسودتك هنا."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "النوافذ",
+      "double_click_label": "فتح الرسائل في نافذة جديدة بالنقر المزدوج",
+      "double_click_description": "النقرة الواحدة تفتح الرسالة بجانب القائمة كالمعتاد.",
+      "restore_label": "إعادة فتح النوافذ عند البدء",
+      "restore_description": "تعود نوافذ الرسائل والمسودات التي كانت مفتوحة عند الخروج."
+    },
+    "attachment": {
+      "open": "فتح",
+      "save_as": "حفظ باسم…",
+      "copy": "نسخ",
+      "copy_failed": "تعذّر نسخ الملف."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "سجّل الدخول باستخدام المتصفح",
     "browser_waiting": "أكمل تسجيل الدخول في المتصفح",
diff --git a/locales/ca/common.json b/locales/ca/common.json
index d2e062a69..368121fb1 100644
--- a/locales/ca/common.json
+++ b/locales/ca/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Aquest missatge s’ha mogut a {folder}.",
     "window_not_ready": "La finestra nova no s’ha obert a temps. L’esborrany es queda aquí."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Finestres",
+      "double_click_label": "Obre els missatges en una finestra nova amb doble clic",
+      "double_click_description": "Un sol clic continua obrint el missatge al costat de la llista.",
+      "restore_label": "Torna a obrir les finestres en iniciar",
+      "restore_description": "Les finestres de missatges i esborranys obertes en sortir tornen a aparèixer."
+    },
+    "attachment": {
+      "open": "Obre",
+      "save_as": "Desa com a…",
+      "copy": "Copia",
+      "copy_failed": "No s’ha pogut copiar el fitxer."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Inicia la sessió amb el navegador",
     "browser_waiting": "Acaba d'iniciar la sessió al navegador",
diff --git a/locales/cs/common.json b/locales/cs/common.json
index 6b1e41754..766227b2e 100644
--- a/locales/cs/common.json
+++ b/locales/cs/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Tato zpráva byla přesunuta do {folder}.",
     "window_not_ready": "Nové okno se neotevřelo včas. Koncept zůstává zde."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Okna",
+      "double_click_label": "Otevírat zprávy v novém okně dvojitým kliknutím",
+      "double_click_description": "Jedním kliknutím se zpráva dál otevře vedle seznamu.",
+      "restore_label": "Při spuštění znovu otevřít okna",
+      "restore_description": "Okna zpráv a konceptů otevřená při ukončení se znovu otevřou."
+    },
+    "attachment": {
+      "open": "Otevřít",
+      "save_as": "Uložit jako…",
+      "copy": "Kopírovat",
+      "copy_failed": "Soubor se nepodařilo zkopírovat."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Přihlásit se v prohlížeči",
     "browser_waiting": "Dokončete přihlášení v prohlížeči",
diff --git a/locales/da/common.json b/locales/da/common.json
index 61d6a1412..483b7e9e0 100644
--- a/locales/da/common.json
+++ b/locales/da/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Denne besked er flyttet til {folder}.",
     "window_not_ready": "Det nye vindue åbnede ikke i tide. Din kladde bliver her."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Vinduer",
+      "double_click_label": "Åbn beskeder i et nyt vindue ved dobbeltklik",
+      "double_click_description": "Et enkelt klik åbner stadig beskeden ved siden af listen.",
+      "restore_label": "Åbn vinduer igen ved start",
+      "restore_description": "Besked- og kladdevinduer, der var åbne, da du lukkede, kommer tilbage."
+    },
+    "attachment": {
+      "open": "Åbn",
+      "save_as": "Gem som…",
+      "copy": "Kopiér",
+      "copy_failed": "Filen kunne ikke kopieres."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Log ind med din browser",
     "browser_waiting": "Gør login færdigt i din browser",
diff --git a/locales/de/common.json b/locales/de/common.json
index eb1ec9a29..f072a7697 100644
--- a/locales/de/common.json
+++ b/locales/de/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Diese Nachricht wurde nach {folder} verschoben.",
     "window_not_ready": "Das neue Fenster wurde nicht rechtzeitig geöffnet. Ihr Entwurf bleibt hier."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Fenster",
+      "double_click_label": "Nachrichten per Doppelklick in einem neuen Fenster öffnen",
+      "double_click_description": "Ein einfacher Klick öffnet die Nachricht weiterhin neben der Liste.",
+      "restore_label": "Fenster beim Start wieder öffnen",
+      "restore_description": "Nachrichten- und Entwurfsfenster, die beim Beenden offen waren, werden wieder geöffnet."
+    },
+    "attachment": {
+      "open": "Öffnen",
+      "save_as": "Speichern unter…",
+      "copy": "Kopieren",
+      "copy_failed": "Die Datei konnte nicht kopiert werden."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Mit dem Browser anmelden",
     "browser_waiting": "Schließen Sie die Anmeldung im Browser ab",
diff --git a/locales/en/common.json b/locales/en/common.json
index 0af0e143f..3fcec9431 100644
--- a/locales/en/common.json
+++ b/locales/en/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "This message was moved to {folder}.",
     "window_not_ready": "The new window did not open in time. Your draft stays here."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Windows",
+      "double_click_label": "Open messages in a new window on double-click",
+      "double_click_description": "A single click still opens the message next to the list.",
+      "restore_label": "Reopen windows at start",
+      "restore_description": "Message and draft windows that were open when you quit come back."
+    },
+    "attachment": {
+      "open": "Open",
+      "save_as": "Save as…",
+      "copy": "Copy",
+      "copy_failed": "The file could not be copied."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Sign in with your browser",
     "browser_waiting": "Finish signing in in your browser",
diff --git a/locales/es/common.json b/locales/es/common.json
index 83aeead77..1487c5b9f 100644
--- a/locales/es/common.json
+++ b/locales/es/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Este mensaje se movió a {folder}.",
     "window_not_ready": "La ventana nueva no se abrió a tiempo. Tu borrador se queda aquí."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Ventanas",
+      "double_click_label": "Abrir mensajes en una ventana nueva con doble clic",
+      "double_click_description": "Un solo clic sigue abriendo el mensaje junto a la lista.",
+      "restore_label": "Volver a abrir las ventanas al iniciar",
+      "restore_description": "Las ventanas de mensajes y borradores abiertas al salir vuelven a aparecer."
+    },
+    "attachment": {
+      "open": "Abrir",
+      "save_as": "Guardar como…",
+      "copy": "Copiar",
+      "copy_failed": "No se pudo copiar el archivo."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Iniciar sesión con el navegador",
     "browser_waiting": "Termina de iniciar sesión en el navegador",
diff --git a/locales/et/common.json b/locales/et/common.json
index 788fb5171..5cf4d5377 100644
--- a/locales/et/common.json
+++ b/locales/et/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "See kiri teisaldati kausta {folder}.",
     "window_not_ready": "Uus aken ei avanenud õigeks ajaks. Mustand jääb siia."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Aknad",
+      "double_click_label": "Ava kirjad topeltklõpsuga uues aknas",
+      "double_click_description": "Üks klõps avab kirja endiselt loendi kõrval.",
+      "restore_label": "Ava aknad käivitamisel uuesti",
+      "restore_description": "Kirja- ja mustandiaknad, mis olid väljumisel avatud, tulevad tagasi."
+    },
+    "attachment": {
+      "open": "Ava",
+      "save_as": "Salvesta nimega…",
+      "copy": "Kopeeri",
+      "copy_failed": "Faili ei saanud kopeerida."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Logi sisse brauseriga",
     "browser_waiting": "Lõpeta sisselogimine brauseris",
diff --git a/locales/fa/common.json b/locales/fa/common.json
index 9eadf3199..7264c52e4 100644
--- a/locales/fa/common.json
+++ b/locales/fa/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "این پیام به {folder} منتقل شد.",
     "window_not_ready": "پنجرهٔ جدید به‌موقع باز نشد. پیش‌نویس شما همین‌جا می‌ماند."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "پنجره‌ها",
+      "double_click_label": "باز کردن پیام‌ها در پنجرهٔ جدید با دوبار کلیک",
+      "double_click_description": "یک کلیک همچنان پیام را کنار فهرست باز می‌کند.",
+      "restore_label": "باز کردن دوبارهٔ پنجره‌ها هنگام شروع",
+      "restore_description": "پنجره‌های پیام و پیش‌نویس که هنگام خروج باز بودند برمی‌گردند."
+    },
+    "attachment": {
+      "open": "باز کردن",
+      "save_as": "ذخیره با نام…",
+      "copy": "کپی",
+      "copy_failed": "فایل کپی نشد."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "ورود با مرورگر",
     "browser_waiting": "ورود را در مرورگر کامل کنید",
diff --git a/locales/fr/common.json b/locales/fr/common.json
index a44af9dbe..bd7f9f641 100644
--- a/locales/fr/common.json
+++ b/locales/fr/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Ce message a été déplacé vers {folder}.",
     "window_not_ready": "La nouvelle fenêtre ne s’est pas ouverte à temps. Votre brouillon reste ici."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Fenêtres",
+      "double_click_label": "Ouvrir les messages dans une nouvelle fenêtre par double-clic",
+      "double_click_description": "Un simple clic ouvre toujours le message à côté de la liste.",
+      "restore_label": "Rouvrir les fenêtres au démarrage",
+      "restore_description": "Les fenêtres de messages et de brouillons ouvertes à la fermeture reviennent."
+    },
+    "attachment": {
+      "open": "Ouvrir",
+      "save_as": "Enregistrer sous…",
+      "copy": "Copier",
+      "copy_failed": "Impossible de copier le fichier."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Se connecter avec le navigateur",
     "browser_waiting": "Terminez la connexion dans votre navigateur",
diff --git a/locales/he/common.json b/locales/he/common.json
index 17580b9a8..6f996e06b 100644
--- a/locales/he/common.json
+++ b/locales/he/common.json
@@ -6502,6 +6502,21 @@
     "message_moved_to": "ההודעה הזו הועברה אל {folder}.",
     "window_not_ready": "החלון החדש לא נפתח בזמן. הטיוטה נשארת כאן."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "חלונות",
+      "double_click_label": "פתיחת הודעות בחלון חדש בלחיצה כפולה",
+      "double_click_description": "לחיצה אחת עדיין פותחת את ההודעה ליד הרשימה.",
+      "restore_label": "פתיחה מחדש של חלונות בהפעלה",
+      "restore_description": "חלונות הודעות וטיוטות שהיו פתוחים ביציאה חוזרים."
+    },
+    "attachment": {
+      "open": "פתיחה",
+      "save_as": "שמירה בשם…",
+      "copy": "העתקה",
+      "copy_failed": "לא ניתן היה להעתיק את הקובץ."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "כניסה באמצעות הדפדפן",
     "browser_waiting": "יש להשלים את הכניסה בדפדפן",
diff --git a/locales/hu/common.json b/locales/hu/common.json
index 474772591..2e93728dc 100644
--- a/locales/hu/common.json
+++ b/locales/hu/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Ezt az üzenetet ide helyezték át: {folder}.",
     "window_not_ready": "Az új ablak nem nyílt meg időben. A piszkozat itt marad."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Ablakok",
+      "double_click_label": "Üzenetek megnyitása új ablakban dupla kattintással",
+      "double_click_description": "Egy kattintás továbbra is a lista mellett nyitja meg az üzenetet.",
+      "restore_label": "Ablakok újranyitása indításkor",
+      "restore_description": "A kilépéskor nyitva lévő üzenet- és piszkozatablakok visszatérnek."
+    },
+    "attachment": {
+      "open": "Megnyitás",
+      "save_as": "Mentés másként…",
+      "copy": "Másolás",
+      "copy_failed": "A fájlt nem sikerült másolni."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Bejelentkezés böngészővel",
     "browser_waiting": "Fejezze be a bejelentkezést a böngészőben",
diff --git a/locales/it/common.json b/locales/it/common.json
index 8cc39c364..10ff1184e 100644
--- a/locales/it/common.json
+++ b/locales/it/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Questo messaggio è stato spostato in {folder}.",
     "window_not_ready": "La nuova finestra non si è aperta in tempo. La bozza rimane qui."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Finestre",
+      "double_click_label": "Apri i messaggi in una nuova finestra con il doppio clic",
+      "double_click_description": "Un solo clic apre comunque il messaggio accanto all’elenco.",
+      "restore_label": "Riapri le finestre all’avvio",
+      "restore_description": "Le finestre di messaggi e bozze aperte all’uscita tornano."
+    },
+    "attachment": {
+      "open": "Apri",
+      "save_as": "Salva con nome…",
+      "copy": "Copia",
+      "copy_failed": "Impossibile copiare il file."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Accedi con il browser",
     "browser_waiting": "Completa l'accesso nel browser",
diff --git a/locales/ja/common.json b/locales/ja/common.json
index e051ceb66..0c5442b8f 100644
--- a/locales/ja/common.json
+++ b/locales/ja/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "このメッセージは {folder} に移動されました。",
     "window_not_ready": "新しいウィンドウが時間内に開きませんでした。下書きはここに残ります。"
   },
+  "desktopUi": {
+    "settings": {
+      "title": "ウィンドウ",
+      "double_click_label": "ダブルクリックでメッセージを新しいウィンドウで開く",
+      "double_click_description": "シングルクリックでは、これまでどおりリストの横に開きます。",
+      "restore_label": "起動時にウィンドウを再び開く",
+      "restore_description": "終了時に開いていたメッセージと下書きのウィンドウが戻ります。"
+    },
+    "attachment": {
+      "open": "開く",
+      "save_as": "名前を付けて保存…",
+      "copy": "コピー",
+      "copy_failed": "ファイルをコピーできませんでした。"
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "ブラウザでサインイン",
     "browser_waiting": "ブラウザでサインインを完了してください",
diff --git a/locales/ko/common.json b/locales/ko/common.json
index e7f7be907..1044f35a6 100644
--- a/locales/ko/common.json
+++ b/locales/ko/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "이 메시지는 {folder}(으)로 이동되었습니다.",
     "window_not_ready": "새 창이 제때 열리지 않았습니다. 임시 보관 메일은 여기에 남아 있습니다."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "창",
+      "double_click_label": "두 번 클릭하면 메시지를 새 창에서 열기",
+      "double_click_description": "한 번 클릭하면 지금처럼 목록 옆에 메시지가 열립니다.",
+      "restore_label": "시작할 때 창 다시 열기",
+      "restore_description": "종료할 때 열려 있던 메시지와 임시보관 창이 다시 열립니다."
+    },
+    "attachment": {
+      "open": "열기",
+      "save_as": "다른 이름으로 저장…",
+      "copy": "복사",
+      "copy_failed": "파일을 복사할 수 없습니다."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "브라우저로 로그인",
     "browser_waiting": "브라우저에서 로그인을 마치세요",
diff --git a/locales/lv/common.json b/locales/lv/common.json
index c07fe9c31..d4a07ddcd 100644
--- a/locales/lv/common.json
+++ b/locales/lv/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Šis ziņojums tika pārvietots uz {folder}.",
     "window_not_ready": "Jaunais logs neatvērās laikus. Melnraksts paliek šeit."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Logi",
+      "double_click_label": "Atvērt ziņojumus jaunā logā ar dubultklikšķi",
+      "double_click_description": "Viens klikšķis joprojām atver ziņojumu blakus sarakstam.",
+      "restore_label": "Startējot atkal atvērt logus",
+      "restore_description": "Ziņojumu un melnrakstu logi, kas bija atvērti izejot, atgriežas."
+    },
+    "attachment": {
+      "open": "Atvērt",
+      "save_as": "Saglabāt kā…",
+      "copy": "Kopēt",
+      "copy_failed": "Failu neizdevās nokopēt."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Pierakstīties ar pārlūku",
     "browser_waiting": "Pabeidziet pierakstīšanos pārlūkā",
diff --git a/locales/mn/common.json b/locales/mn/common.json
index 4633a5d6d..217981f08 100644
--- a/locales/mn/common.json
+++ b/locales/mn/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Энэ мессежийг {folder} руу зөөсөн.",
     "window_not_ready": "Шинэ цонх цагтаа нээгдсэнгүй. Таны ноорог энд үлдэнэ."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Цонх",
+      "double_click_label": "Давхар товшиход мессежийг шинэ цонхонд нээх",
+      "double_click_description": "Нэг товшилт мессежийг жагсаалтын хажууд нээсээр байна.",
+      "restore_label": "Эхлэхэд цонхнуудыг дахин нээх",
+      "restore_description": "Гарах үед нээлттэй байсан мессеж, ноорог цонхнууд буцаж нээгдэнэ."
+    },
+    "attachment": {
+      "open": "Нээх",
+      "save_as": "Өөрөөр хадгалах…",
+      "copy": "Хуулах",
+      "copy_failed": "Файлыг хуулж чадсангүй."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Хөтчөөр нэвтрэх",
     "browser_waiting": "Нэвтрэлтээ хөтөч дээр дуусгана уу",
diff --git a/locales/nb/common.json b/locales/nb/common.json
index d2e1a518e..568697bf8 100644
--- a/locales/nb/common.json
+++ b/locales/nb/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Denne meldingen ble flyttet til {folder}.",
     "window_not_ready": "Det nye vinduet åpnet seg ikke i tide. Utkastet blir her."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Vinduer",
+      "double_click_label": "Åpne meldinger i et nytt vindu ved dobbeltklikk",
+      "double_click_description": "Et enkelt klikk åpner fortsatt meldingen ved siden av listen.",
+      "restore_label": "Åpne vinduer på nytt ved start",
+      "restore_description": "Meldings- og utkastvinduer som var åpne da du avsluttet, kommer tilbake."
+    },
+    "attachment": {
+      "open": "Åpne",
+      "save_as": "Lagre som…",
+      "copy": "Kopier",
+      "copy_failed": "Filen kunne ikke kopieres."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Logg på med nettleseren",
     "browser_waiting": "Fullfør påloggingen i nettleseren",
diff --git a/locales/nl/common.json b/locales/nl/common.json
index b704a66fc..2bb1777e5 100644
--- a/locales/nl/common.json
+++ b/locales/nl/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Dit bericht is verplaatst naar {folder}.",
     "window_not_ready": "Het nieuwe venster is niet op tijd geopend. Je concept blijft hier."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Vensters",
+      "double_click_label": "Berichten openen in een nieuw venster met dubbelklikken",
+      "double_click_description": "Eén klik opent het bericht nog steeds naast de lijst.",
+      "restore_label": "Vensters opnieuw openen bij het starten",
+      "restore_description": "Bericht- en conceptvensters die open waren bij het afsluiten, komen terug."
+    },
+    "attachment": {
+      "open": "Openen",
+      "save_as": "Opslaan als…",
+      "copy": "Kopiëren",
+      "copy_failed": "Het bestand kon niet worden gekopieerd."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Inloggen met je browser",
     "browser_waiting": "Rond het inloggen af in je browser",
diff --git a/locales/pl/common.json b/locales/pl/common.json
index 8ccc30784..32570ddf4 100644
--- a/locales/pl/common.json
+++ b/locales/pl/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Ta wiadomość została przeniesiona do {folder}.",
     "window_not_ready": "Nowe okno nie otworzyło się na czas. Twój szkic zostaje tutaj."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Okna",
+      "double_click_label": "Otwieraj wiadomości w nowym oknie po dwukrotnym kliknięciu",
+      "double_click_description": "Pojedyncze kliknięcie nadal otwiera wiadomość obok listy.",
+      "restore_label": "Otwieraj okna ponownie przy starcie",
+      "restore_description": "Okna wiadomości i wersji roboczych otwarte przy zamykaniu wrócą."
+    },
+    "attachment": {
+      "open": "Otwórz",
+      "save_as": "Zapisz jako…",
+      "copy": "Kopiuj",
+      "copy_failed": "Nie udało się skopiować pliku."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Zaloguj się w przeglądarce",
     "browser_waiting": "Dokończ logowanie w przeglądarce",
diff --git a/locales/pt/common.json b/locales/pt/common.json
index 188b256f8..4bc75f09e 100644
--- a/locales/pt/common.json
+++ b/locales/pt/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Esta mensagem foi movida para {folder}.",
     "window_not_ready": "A nova janela não abriu a tempo. O seu rascunho fica aqui."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Janelas",
+      "double_click_label": "Abrir mensagens numa nova janela com duplo clique",
+      "double_click_description": "Um único clique continua a abrir a mensagem junto à lista.",
+      "restore_label": "Reabrir janelas ao iniciar",
+      "restore_description": "As janelas de mensagens e rascunhos abertas ao sair voltam a aparecer."
+    },
+    "attachment": {
+      "open": "Abrir",
+      "save_as": "Guardar como…",
+      "copy": "Copiar",
+      "copy_failed": "Não foi possível copiar o ficheiro."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Entrar com o navegador",
     "browser_waiting": "Termine de entrar no navegador",
diff --git a/locales/ro/common.json b/locales/ro/common.json
index ae31839c2..6fce2943e 100644
--- a/locales/ro/common.json
+++ b/locales/ro/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Acest mesaj a fost mutat în {folder}.",
     "window_not_ready": "Fereastra nouă nu s-a deschis la timp. Ciorna rămâne aici."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Ferestre",
+      "double_click_label": "Deschide mesajele într-o fereastră nouă la dublu clic",
+      "double_click_description": "Un singur clic deschide în continuare mesajul lângă listă.",
+      "restore_label": "Redeschide ferestrele la pornire",
+      "restore_description": "Ferestrele de mesaje și ciorne deschise la ieșire revin."
+    },
+    "attachment": {
+      "open": "Deschide",
+      "save_as": "Salvează ca…",
+      "copy": "Copiază",
+      "copy_failed": "Fișierul nu a putut fi copiat."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Conectează-te cu browserul",
     "browser_waiting": "Finalizează conectarea în browser",
diff --git a/locales/ru/common.json b/locales/ru/common.json
index a9ee1c65c..887bc0f8e 100644
--- a/locales/ru/common.json
+++ b/locales/ru/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Это письмо перемещено в {folder}.",
     "window_not_ready": "Новое окно не открылось вовремя. Черновик остаётся здесь."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Окна",
+      "double_click_label": "Открывать письма в новом окне двойным щелчком",
+      "double_click_description": "Одиночный щелчок по-прежнему открывает письмо рядом со списком.",
+      "restore_label": "Снова открывать окна при запуске",
+      "restore_description": "Окна писем и черновиков, открытые при выходе, вернутся."
+    },
+    "attachment": {
+      "open": "Открыть",
+      "save_as": "Сохранить как…",
+      "copy": "Копировать",
+      "copy_failed": "Не удалось скопировать файл."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Войти через браузер",
     "browser_waiting": "Завершите вход в браузере",
diff --git a/locales/sk/common.json b/locales/sk/common.json
index a018ba55a..78493d1b7 100644
--- a/locales/sk/common.json
+++ b/locales/sk/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Táto správa bola presunutá do {folder}.",
     "window_not_ready": "Nové okno sa neotvorilo včas. Koncept zostáva tu."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Okná",
+      "double_click_label": "Otvárať správy v novom okne dvojitým kliknutím",
+      "double_click_description": "Jedným kliknutím sa správa stále otvorí vedľa zoznamu.",
+      "restore_label": "Pri spustení znova otvoriť okná",
+      "restore_description": "Okná správ a konceptov otvorené pri ukončení sa vrátia."
+    },
+    "attachment": {
+      "open": "Otvoriť",
+      "save_as": "Uložiť ako…",
+      "copy": "Kopírovať",
+      "copy_failed": "Súbor sa nepodarilo skopírovať."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Prihlásiť sa v prehliadači",
     "browser_waiting": "Dokončite prihlásenie v prehliadači",
diff --git a/locales/th/common.json b/locales/th/common.json
index 065a7afbc..510ae7960 100644
--- a/locales/th/common.json
+++ b/locales/th/common.json
@@ -6509,6 +6509,21 @@
     "message_moved_to": "ข้อความนี้ถูกย้ายไปยัง {folder}",
     "window_not_ready": "หน้าต่างใหม่เปิดไม่ทัน แบบร่างของคุณยังอยู่ที่นี่"
   },
+  "desktopUi": {
+    "settings": {
+      "title": "หน้าต่าง",
+      "double_click_label": "เปิดข้อความในหน้าต่างใหม่เมื่อดับเบิลคลิก",
+      "double_click_description": "คลิกครั้งเดียวยังคงเปิดข้อความข้างรายการ",
+      "restore_label": "เปิดหน้าต่างอีกครั้งเมื่อเริ่มต้น",
+      "restore_description": "หน้าต่างข้อความและฉบับร่างที่เปิดอยู่ตอนออกจะกลับมา"
+    },
+    "attachment": {
+      "open": "เปิด",
+      "save_as": "บันทึกเป็น…",
+      "copy": "คัดลอก",
+      "copy_failed": "คัดลอกไฟล์ไม่ได้"
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "ลงชื่อเข้าใช้ด้วยเบราว์เซอร์",
     "browser_waiting": "ลงชื่อเข้าใช้ให้เสร็จในเบราว์เซอร์",
diff --git a/locales/tr/common.json b/locales/tr/common.json
index 81acedbf7..d06d1ab23 100644
--- a/locales/tr/common.json
+++ b/locales/tr/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Bu ileti {folder} klasörüne taşındı.",
     "window_not_ready": "Yeni pencere zamanında açılmadı. Taslağınız burada kalıyor."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Pencereler",
+      "double_click_label": "İletileri çift tıklamayla yeni pencerede aç",
+      "double_click_description": "Tek tıklama iletiyi yine listenin yanında açar.",
+      "restore_label": "Başlangıçta pencereleri yeniden aç",
+      "restore_description": "Çıkarken açık olan ileti ve taslak pencereleri geri gelir."
+    },
+    "attachment": {
+      "open": "Aç",
+      "save_as": "Farklı kaydet…",
+      "copy": "Kopyala",
+      "copy_failed": "Dosya kopyalanamadı."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Tarayıcıyla oturum aç",
     "browser_waiting": "Oturum açmayı tarayıcınızda tamamlayın",
diff --git a/locales/uk/common.json b/locales/uk/common.json
index 42dbd1aba..df795476e 100644
--- a/locales/uk/common.json
+++ b/locales/uk/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "Цього листа переміщено в {folder}.",
     "window_not_ready": "Нове вікно не відкрилося вчасно. Чернетка залишається тут."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Вікна",
+      "double_click_label": "Відкривати листи в новому вікні подвійним клацанням",
+      "double_click_description": "Одне клацання, як і раніше, відкриває лист поруч зі списком.",
+      "restore_label": "Знову відкривати вікна під час запуску",
+      "restore_description": "Вікна листів і чернеток, відкриті під час виходу, повернуться."
+    },
+    "attachment": {
+      "open": "Відкрити",
+      "save_as": "Зберегти як…",
+      "copy": "Копіювати",
+      "copy_failed": "Не вдалося скопіювати файл."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Увійти через браузер",
     "browser_waiting": "Завершіть вхід у браузері",
diff --git a/locales/vi/common.json b/locales/vi/common.json
index 9cbcd8bd3..7d40138ff 100644
--- a/locales/vi/common.json
+++ b/locales/vi/common.json
@@ -6513,6 +6513,21 @@
     "message_moved_to": "Thư này đã được chuyển đến {folder}.",
     "window_not_ready": "Cửa sổ mới không mở kịp. Bản nháp của bạn vẫn ở đây."
   },
+  "desktopUi": {
+    "settings": {
+      "title": "Cửa sổ",
+      "double_click_label": "Mở thư trong cửa sổ mới khi nhấp đúp",
+      "double_click_description": "Nhấp một lần vẫn mở thư bên cạnh danh sách.",
+      "restore_label": "Mở lại cửa sổ khi khởi động",
+      "restore_description": "Các cửa sổ thư và bản nháp đang mở khi thoát sẽ trở lại."
+    },
+    "attachment": {
+      "open": "Mở",
+      "save_as": "Lưu thành…",
+      "copy": "Sao chép",
+      "copy_failed": "Không thể sao chép tệp."
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "Đăng nhập bằng trình duyệt",
     "browser_waiting": "Hoàn tất đăng nhập trong trình duyệt",
diff --git a/locales/zh-TW/common.json b/locales/zh-TW/common.json
index 5ba44316f..2a682799e 100644
--- a/locales/zh-TW/common.json
+++ b/locales/zh-TW/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "這封郵件已移到 {folder}。",
     "window_not_ready": "新視窗未能及時開啟。你的草稿仍保留在這裡。"
   },
+  "desktopUi": {
+    "settings": {
+      "title": "視窗",
+      "double_click_label": "按兩下時在新視窗中開啟郵件",
+      "double_click_description": "按一下仍會在清單旁開啟郵件。",
+      "restore_label": "啟動時重新開啟視窗",
+      "restore_description": "結束時開啟的郵件和草稿視窗會恢復。"
+    },
+    "attachment": {
+      "open": "開啟",
+      "save_as": "另存新檔…",
+      "copy": "複製",
+      "copy_failed": "無法複製檔案。"
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "使用瀏覽器登入",
     "browser_waiting": "請在瀏覽器中完成登入",
diff --git a/locales/zh/common.json b/locales/zh/common.json
index f53c82da4..1aca2e30c 100644
--- a/locales/zh/common.json
+++ b/locales/zh/common.json
@@ -6501,6 +6501,21 @@
     "message_moved_to": "这封邮件已移动到 {folder}。",
     "window_not_ready": "新窗口未能及时打开。你的草稿仍保留在这里。"
   },
+  "desktopUi": {
+    "settings": {
+      "title": "窗口",
+      "double_click_label": "双击时在新窗口中打开邮件",
+      "double_click_description": "单击仍会在列表旁打开邮件。",
+      "restore_label": "启动时重新打开窗口",
+      "restore_description": "退出时打开的邮件和草稿窗口会恢复。"
+    },
+    "attachment": {
+      "open": "打开",
+      "save_as": "另存为…",
+      "copy": "复制",
+      "copy_failed": "无法复制文件。"
+    }
+  },
   "desktop_sign_in": {
     "browser_button": "使用浏览器登录",
     "browser_waiting": "请在浏览器中完成登录",