fix(browser): load newly opened background tabs (#19633)

* fix(browser): admit newly opened background pages

* fix(browser): scope background page mount admission

---------

Co-authored-by: Merge Sim <sim@local>
(cherry picked from commit 94a64cf40f)

src/renderer/src/components/browser-pane/assemble-chrome/BrowserPaneOverlayLayer.tsx

@@ -15,6 +15,7 @@ import {
   useClientHostedBrowserRows
 } from '@/lib/pane-manager/client-hosted-browser-row-state'
 import { ClientHostedBrowserHostRowPane } from '../client-hosted-browser-host-row-pane'
+import { useAnyBrowserPageMountAdmission } from '../host-guest/browser-page-mount-admission'
 
 // Why: Electron <webview> destroys its guest on DOM reparent, so BrowserPanes render at worktree level and moving a tab between groups only swaps the overlay's CSS position-anchor.
 
@@ -60,7 +61,8 @@ const BrowserOverlaySlot = memo(function BrowserOverlaySlot({
       ? browserTab.pageIds
       : [browserTab.activePageId ?? browserTab.id]
   const needsGuestPaint = useBrowserGuestPaintRetention(browserPageIds)
-  const isPaintable = isActive || needsGuestPaint
+  const isMountAdmitted = useAnyBrowserPageMountAdmission(browserPageIds)
+  const isPaintable = isActive || needsGuestPaint || isMountAdmitted
   // Why: CSS anchor positioning pins the overlay to its owning group's body — a tab move only swaps positionAnchor, no measurement/state.
   // Orphan branch (no anchorName) stays display:none until the tab is reassigned or destroyed.
   const style: React.CSSProperties = useMemo(

src/renderer/src/components/browser-pane/assemble-chrome/browser-workspace-pane.tsx

@@ -22,6 +22,10 @@ import { WorkspaceDocPagePane } from '../workspace-doc/workspace-doc-page-pane'
 import { DeferredBrowserContent } from './DeferredBrowserContent'
 import { isBrowserPagePanePaintable } from '../host-guest/browser-page-paintability'
 import { SshRoutedBrowserPageGate } from './ssh-routed-browser-page-gate'
+import {
+  isBrowserPageMountAdmitted,
+  useAnyBrowserPageMountAdmission
+} from '../host-guest/browser-page-mount-admission'
 
 export default function BrowserPane({
   browserTab,
@@ -71,6 +75,7 @@ export default function BrowserPane({
     () => localBrowserPages.map((page) => page.id),
     [localBrowserPages]
   )
+  const hasAdmittedPage = useAnyBrowserPageMountAdmission(localBrowserPageIds)
   const pageDriver = useBrowserDriverForPage(activeBrowserPageId)
   // Why: a runtime-backed page is streamed, never locally driven, so its driver must read idle.
   const activeBrowserDriver = runtimeEnvironmentActive ? IDLE_BROWSER_DRIVER : pageDriver
@@ -166,7 +171,9 @@ export default function BrowserPane({
                   key={page.id}
                   retainMounted={isWorktreeActive}
                   mountEligible={isBrowserPagePanePaintable({
-                    isActive: isActive && page.id === activeBrowserPageId,
+                    isActive:
+                      (isActive && page.id === activeBrowserPageId) ||
+                      (hasAdmittedPage && isBrowserPageMountAdmitted(page.id)),
                     isAutomationVisible: automationVisiblePageIds.has(page.id),
                     isMobileDriven: mobileDrivenPageIds.has(page.id),
                     hasRemoteViewer: remotelyViewedPageIds.has(page.id)

src/renderer/src/components/browser-pane/host-guest/browser-page-mount-admission.ts

@@ -0,0 +1,63 @@
+import { useSyncExternalStore } from 'react'
+
+// Newly requested pages must start a guest even when opened in the background. Restored pages are
+// deliberately absent so worktree restoration can remain lazy.
+const admittedPageIds = new Set<string>()
+const listeners = new Set<() => void>()
+let version = 0
+
+export function isBrowserPageMountAdmitted(pageId: string): boolean {
+  return admittedPageIds.has(pageId)
+}
+
+function emit(): void {
+  version += 1
+  for (const listener of listeners) {
+    listener()
+  }
+}
+
+export function admitBrowserPageMount(pageId: string): void {
+  if (admittedPageIds.has(pageId)) {
+    return
+  }
+  admittedPageIds.add(pageId)
+  emit()
+}
+
+export function releaseBrowserPageMount(pageId: string): void {
+  if (!admittedPageIds.delete(pageId)) {
+    return
+  }
+  emit()
+}
+
+export function useBrowserPageMountAdmission(pageId: string): boolean {
+  useSyncExternalStore(
+    (listener) => {
+      listeners.add(listener)
+      return () => listeners.delete(listener)
+    },
+    () => {
+      void version
+      return isBrowserPageMountAdmitted(pageId)
+    },
+    () => false
+  )
+  return isBrowserPageMountAdmitted(pageId)
+}
+
+export function useAnyBrowserPageMountAdmission(pageIds: readonly string[]): boolean {
+  useSyncExternalStore(
+    (listener) => {
+      listeners.add(listener)
+      return () => listeners.delete(listener)
+    },
+    () => {
+      void version
+      return pageIds.some(isBrowserPageMountAdmitted)
+    },
+    () => false
+  )
+  return pageIds.some(isBrowserPageMountAdmitted)
+}

src/renderer/src/store/slices/browser/browser-close-actions.ts

@@ -13,6 +13,7 @@ import { closeRemoteBrowserPageInOwningEnvironment } from './browser-remote-clos
 import { releaseDocPreviewGrant } from '@/lib/doc-preview-grants'
 import { destroyWorkspaceWebviews } from '../browser-webview-cleanup'
 import { omitRecordKeys } from '../worktrees/teardown/record-key-omission'
+import { releaseBrowserPageMount } from '@/components/browser-pane/host-guest/browser-page-mount-admission'
 
 export function createBrowserCloseActions(
   set: BrowserSliceSet,
@@ -28,6 +29,7 @@ export function createBrowserCloseActions(
       // grant is the only authority the preview scheme honors — a closed document must stop being
       // readable, and it must stop being readable even if the reducer bails out below.
       let docPageIdsToRelease: string[] = []
+      let closedPagesForMountRelease: string[] = []
       let activeBrowserWorktreeIdToNotify: string | null = null
       set((s) => {
         let owningWorktreeId: string | null = null
@@ -49,6 +51,7 @@ export function createBrowserCloseActions(
         }
 
         const closedPages = s.browserPagesByWorkspace[tabId] ?? []
+        closedPagesForMountRelease = closedPages.map((page) => page.id)
         const nextBrowserPagesByWorkspace = { ...s.browserPagesByWorkspace }
         delete nextBrowserPagesByWorkspace[tabId]
         const nextBrowserAnnotationsByPageId = { ...s.browserAnnotationsByPageId }
@@ -179,6 +182,9 @@ export function createBrowserCloseActions(
       for (const docPageId of docPageIdsToRelease) {
         releaseDocPreviewGrant(docPageId)
       }
+      for (const pageId of closedPagesForMountRelease) {
+        releaseBrowserPageMount(pageId)
+      }
 
       for (const tabs of Object.values(get().unifiedTabsByWorktree)) {
         const workspaceItem = tabs.find(

src/renderer/src/store/slices/browser/browser-page-create-actions.ts

@@ -13,6 +13,10 @@ import {
 import { ORCA_BROWSER_BLANK_URL } from '../../../../../shared/constants'
 import { closeRemoteBrowserPageInOwningEnvironment } from './browser-remote-close'
 import { releaseDocPreviewGrant } from '@/lib/doc-preview-grants'
+import {
+  admitBrowserPageMount,
+  releaseBrowserPageMount
+} from '@/components/browser-pane/host-guest/browser-page-mount-admission'
 
 export function createBrowserPageCreateActions(
   set: BrowserSliceSet,
@@ -33,6 +37,9 @@ export function createBrowserPageCreateActions(
         undefined,
         options?.docLocation
       )
+      if (!options?.browserRuntimeEnvironmentId && !options?.docLocation) {
+        admitBrowserPageMount(page.id)
+      }
 
       set((s) => {
         const pages = s.browserPagesByWorkspace[workspaceId] ?? []
@@ -94,6 +101,7 @@ export function createBrowserPageCreateActions(
     },
 
     closeBrowserPage: (pageId) => {
+      releaseBrowserPageMount(pageId)
       let closedWorkspaceIdForLabel: string | null = null
       let docPageIdToRelease: string | null = null
       const remotePagesToClose: { worktreeId: string; handle: RemoteBrowserPageHandle }[] = []

src/renderer/src/store/slices/browser/browser-tab-actions.ts

@@ -17,6 +17,7 @@ import {
 } from '../browser-page-records'
 import { getBrowserSessionProfileHostId } from './browser-host-state'
 import { getRuntimeEnvironmentIdForWorktree } from '@/lib/worktree-runtime-owner'
+import { admitBrowserPageMount } from '@/components/browser-pane/host-guest/browser-page-mount-admission'
 
 export function createBrowserTabActions(
   set: BrowserSliceSet,
@@ -48,6 +49,9 @@ export function createBrowserTabActions(
         browserPageId,
         options?.docLocation
       )
+      if (!options?.browserRuntimeEnvironmentId && !options?.docLocation) {
+        admitBrowserPageMount(page.id)
+      }
       // Why: with no explicit profile, inherit the user's default so a Settings preference applies to new tabs.
       const sessionProfileId =
         options?.sessionProfileId !== undefined