fix(desktop): preserve chat view across tab switches

desktop/src/components/chat/ChatInput.test.tsx

@@ -522,6 +522,27 @@ describe('ChatInput file mentions', () => {
     })
   })
 
+  it('keeps a retained conversation draft when settings becomes the selected tab', () => {
+    useTabStore.setState((state) => ({
+      tabs: [...state.tabs, { sessionId: '__settings__', title: 'Settings', type: 'settings', status: 'idle' }],
+    }))
+    const { rerender } = render(<ChatInput sessionId={sessionId} />)
+    setComposerText('keep this draft', 15)
+    act(() => getComposerElement().focus())
+    expect(getComposerElement()).toHaveFocus()
+
+    act(() => useTabStore.getState().setActiveTab('__settings__'))
+    rerender(<ChatInput sessionId={sessionId} visible={false} />)
+
+    expect(getComposerText()).toBe('keep this draft')
+    expect(getComposerElement()).not.toHaveFocus()
+    expect(useChatStore.getState().sessions['__settings__']).toBeUndefined()
+
+    act(() => useTabStore.getState().setActiveTab(sessionId))
+    rerender(<ChatInput sessionId={sessionId} visible />)
+    expect(getComposerText()).toBe('keep this draft')
+  })
+
   it('keeps the unsent draft when switching project on an empty active session', async () => {
     installElectronFileHost()
     mocks.dialogOpen.mockResolvedValueOnce('/other')

desktop/src/components/chat/ChatInput.tsx

@@ -79,6 +79,8 @@ type Attachment = ComposerAttachment
 type ChatInputProps = {
   variant?: 'default' | 'hero'
   compact?: boolean
+  sessionId?: string
+  visible?: boolean
 }
 
 const EMPTY_COMPOSER_REFERENCES: ComposerReferenceCandidate[] = []
@@ -136,7 +138,7 @@ function insertComposerTokenAtRange(value: string, start: number, end: number, t
   }
 }
 
-export function ChatInput({ variant = 'default', compact = false }: ChatInputProps) {
+export function ChatInput({ variant = 'default', compact = false, sessionId, visible = true }: ChatInputProps) {
   const t = useTranslation()
   const isMobileComposer = useMobileViewport() && !isDesktopRuntime()
   // The shell, not the panel inside it: the panel's own `max-w` changes with
@@ -206,9 +208,10 @@ export function ChatInput({ variant = 'default', compact = false }: ChatInputPro
     sendQueuedUserMessage,
     setPreparingTurn,
   } = useChatStore()
-  const activeTabId = useTabStore((s) => s.activeTabId)
+  const selectedTabId = useTabStore((s) => s.activeTabId)
+  const activeTabId = sessionId ?? selectedTabId
   const activeTabType = useTabStore((s) =>
-    s.tabs.find((tab) => tab.sessionId === s.activeTabId)?.type,
+    s.tabs.find((tab) => tab.sessionId === (sessionId ?? s.activeTabId))?.type,
   )
   const sessionState = useChatStore((s) => activeTabId ? s.sessions[activeTabId] : undefined)
   const repositoryLaunchDraft = sessionState?.repositoryLaunchDraft
@@ -408,8 +411,14 @@ export function ChatInput({ variant = 'default', compact = false }: ChatInputPro
   }, [mentions])
 
   useEffect(() => {
-    composerRef.current?.focus()
-  }, [isActive])
+    if (visible) composerRef.current?.focus()
+  }, [isActive, visible])
+
+  useEffect(() => {
+    if (visible) return
+    const focused = document.activeElement
+    if (focused instanceof HTMLElement && panelRef.current?.contains(focused)) focused.blur()
+  }, [visible])
 
   useEffect(() => {
     if (!composerPrefill || !activeTabId) return
@@ -439,7 +448,7 @@ export function ChatInput({ variant = 'default', compact = false }: ChatInputPro
     setAtCursorPos(-1)
 
     requestAnimationFrame(() => {
-      composerRef.current?.focus()
+      if (visible) composerRef.current?.focus()
       if (composerPrefill.mode !== 'append') {
         composerRef.current?.setSelectionOffsets(composerPrefill.text.length)
       }
@@ -451,6 +460,7 @@ export function ChatInput({ variant = 'default', compact = false }: ChatInputPro
     composerPrefill,
     setComposerAttachments,
     setComposerInput,
+    visible,
   ])
 
   useEffect(() => {
@@ -473,7 +483,7 @@ export function ChatInput({ variant = 'default', compact = false }: ChatInputPro
     clearComposerInsertion(activeTabId, composerInsertion.nonce)
 
     requestAnimationFrame(() => {
-      composerRef.current?.focus()
+      if (visible) composerRef.current?.focus()
       composerRef.current?.setSelectionOffsets(next.cursorPos)
     })
   }, [
@@ -481,6 +491,7 @@ export function ChatInput({ variant = 'default', compact = false }: ChatInputPro
     addWorkspaceReference,
     clearComposerInsertion,
     composerInsertion,
+    visible,
     isMemberSession,
     setComposerInput,
   ])

desktop/src/components/layout/ContentRouter.test.tsx

@@ -300,6 +300,29 @@ describe('ContentRouter tab surfaces', () => {
     expect(screen.getByTestId('settings-page')).toBeInTheDocument()
     expect(useTabStore.getState().tabs.find(tab => tab.sessionId === 'session-1')).toMatchObject({ type: 'session' })
   })
+
+  it('keeps the current conversation mounted while settings is open', () => {
+    useTabStore.setState({
+      tabs: [
+        { sessionId: 'session-1', title: 'Chat', type: 'session', status: 'idle' },
+        { sessionId: SETTINGS_TAB_ID, title: 'Settings', type: 'settings', status: 'idle' },
+      ],
+      activeTabId: 'session-1',
+    })
+
+    render(<ContentRouter />)
+    const conversation = screen.getByTestId('active-session')
+
+    act(() => useTabStore.getState().setActiveTab(SETTINGS_TAB_ID))
+    expect(screen.getByTestId('settings-page')).toBeInTheDocument()
+    expect(conversation).toBeInTheDocument()
+    expect(conversation.closest('[aria-hidden]')).toHaveAttribute('aria-hidden', 'true')
+    expect(conversation.closest('[aria-hidden]')).toHaveAttribute('inert')
+
+    act(() => useTabStore.getState().setActiveTab('session-1'))
+    expect(screen.getByTestId('active-session')).toBe(conversation)
+    expect(screen.queryByTestId('settings-page')).not.toBeInTheDocument()
+  })
 })
 
 it('routes the independent connectors tab', () => {

desktop/src/components/layout/ContentRouter.tsx

@@ -1,4 +1,4 @@
-import { useEffect, type ReactNode } from 'react'
+import { useEffect, useState, type ReactNode } from 'react'
 import { useTabStore } from '../../stores/tabStore'
 import { EmptySession } from '../../pages/EmptySession'
 import { ActiveSession } from '../../pages/ActiveSession'
@@ -17,6 +17,18 @@ export function ContentRouter() {
   const tabs = useTabStore((s) => s.tabs)
   const activeTabType = tabs.find((t) => t.sessionId === activeTabId)?.type
   const terminalTabs = tabs.filter((tab) => tab.type === 'terminal')
+  const activeSessionId = activeTabType === 'session' ? activeTabId : null
+  const [lastSessionId, setLastSessionId] = useState<string | null>(activeSessionId)
+  const retainedSessionId = activeSessionId ?? (
+    tabs.some((tab) => tab.sessionId === lastSessionId && tab.type === 'session')
+      ? lastSessionId
+      : null
+  )
+
+  useEffect(() => {
+    if (activeSessionId) setLastSessionId(activeSessionId)
+    else if (lastSessionId && !retainedSessionId) setLastSessionId(null)
+  }, [activeSessionId, lastSessionId, retainedSessionId])
 
   useEffect(() => {
     if (activeTabType !== 'workbench') return
@@ -79,12 +91,24 @@ export function ContentRouter() {
     page = teamTab?.teamLeadSessionId
       ? <AgentTeamsWorkbenchTab tabId={activeTabId} leadSessionId={teamTab.teamLeadSessionId} />
       : <EmptySession />
-  } else if (activeTabType !== 'terminal') {
-    page = <ActiveSession />
+  } else if (activeTabType !== 'terminal' && activeTabType !== 'session') {
+    page = <EmptySession />
   }
 
   return (
     <div className="relative min-h-0 flex-1 overflow-hidden">
+      {retainedSessionId && (
+        <div
+          aria-hidden={!activeSessionId}
+          {...(activeSessionId ? {} : { inert: '' })}
+          data-testid="session-tab-panel"
+          className={`absolute inset-0 flex min-h-0 flex-col overflow-hidden ${
+            activeSessionId ? 'z-10 opacity-100' : 'pointer-events-none z-0 opacity-0'
+          }`}
+        >
+          <ActiveSession sessionId={retainedSessionId} active={Boolean(activeSessionId)} />
+        </div>
+      )}
       {page && (
         <div className="absolute inset-0 z-10 flex min-h-0 flex-col overflow-hidden">
           {page}

desktop/src/pages/ActiveSession.test.tsx

@@ -37,14 +37,14 @@ vi.mock('../hooks/useMobileViewport', () => ({
 }))
 
 vi.mock('../components/chat/MessageList', () => ({
-  MessageList: ({ compact }: { compact?: boolean }) => (
-    <div data-testid="message-list" data-compact={compact ? 'true' : 'false'} />
+  MessageList: ({ compact, sessionId }: { compact?: boolean; sessionId?: string }) => (
+    <div data-testid="message-list" data-compact={compact ? 'true' : 'false'} data-session-id={sessionId} />
   ),
 }))
 
 vi.mock('../components/chat/ChatInput', () => ({
-  ChatInput: ({ compact, variant }: { compact?: boolean; variant?: string }) => (
-    <div data-testid="chat-input" data-compact={compact ? 'true' : 'false'} data-variant={variant} />
+  ChatInput: ({ compact, variant, sessionId, visible }: { compact?: boolean; variant?: string; sessionId?: string; visible?: boolean }) => (
+    <div data-testid="chat-input" data-compact={compact ? 'true' : 'false'} data-variant={variant} data-session-id={sessionId} data-visible={visible ? 'true' : 'false'} />
   ),
 }))
 
@@ -141,6 +141,55 @@ afterEach(() => {
 })
 
 describe('ActiveSession task polling', () => {
+  it('keeps the same message list bound to its session while settings is selected', () => {
+    const sessionId = 'retained-session'
+    useSessionStore.setState({
+      sessions: [{
+        id: sessionId,
+        title: 'Retained Session',
+        createdAt: '2026-05-07T00:00:00.000Z',
+        modifiedAt: '2026-05-07T00:00:00.000Z',
+        messageCount: 1,
+        projectPath: '/workspace/project',
+        workDir: '/workspace/project',
+        workDirExists: true,
+      }],
+      activeSessionId: sessionId,
+    })
+    useTabStore.setState({
+      tabs: [
+        { sessionId, title: 'Retained Session', type: 'session', status: 'idle' },
+        { sessionId: '__settings__', title: 'Settings', type: 'settings', status: 'idle' },
+      ],
+      activeTabId: sessionId,
+    })
+    useChatStore.setState({
+      sessions: {
+        [sessionId]: {
+          ...createDefaultSessionState(),
+          connectionState: 'connected',
+          messages: [{ id: 'existing', type: 'assistant_text', content: 'ready', timestamp: 1 }],
+          historyStatus: 'ready',
+          historyHydrated: true,
+        },
+      },
+    })
+
+    const { rerender } = render(<ActiveSession sessionId={sessionId} active />)
+    const messageList = screen.getByTestId('message-list')
+    const chatInput = screen.getByTestId('chat-input')
+
+    act(() => useTabStore.getState().setActiveTab('__settings__'))
+    rerender(<ActiveSession sessionId={sessionId} active={false} />)
+
+    expect(screen.getByTestId('message-list')).toBe(messageList)
+    expect(screen.getByTestId('chat-input')).toBe(chatInput)
+    expect(messageList).toHaveAttribute('data-session-id', sessionId)
+    expect(chatInput).toHaveAttribute('data-session-id', sessionId)
+    expect(chatInput).toHaveAttribute('data-visible', 'false')
+    expect(useChatStore.getState().sessions['__settings__']).toBeUndefined()
+  })
+
   it('shows cleaned worktrees as retained history and uses the source project for tools', () => {
     const sessionId = 'cleaned-worktree-session'
     useSettingsStore.setState({ locale: 'en' })

desktop/src/pages/ActiveSession.tsx

@@ -316,11 +316,12 @@ function TerminalResizeHandle() {
   )
 }
 
-export function ActiveSession() {
+export function ActiveSession({ sessionId, active = true }: { sessionId?: string; active?: boolean } = {}) {
   const isMobileLayout = useMobileViewport() && !isDesktopRuntime()
   const workbenchPanelRef = useRef<HTMLElement>(null)
-  const activeTabId = useTabStore((s) => s.activeTabId)
-  const activeTabType = useTabStore((s) => s.tabs.find((tab) => tab.sessionId === s.activeTabId)?.type ?? null)
+  const selectedTabId = useTabStore((s) => s.activeTabId)
+  const activeTabId = sessionId ?? selectedTabId
+  const activeTabType = useTabStore((s) => s.tabs.find((tab) => tab.sessionId === (sessionId ?? s.activeTabId))?.type ?? null)
   const sessions = useSessionStore((s) => s.sessions)
   const connectToSession = useChatStore((s) => s.connectToSession)
   const stopBackgroundTask = useChatStore((s) => s.stopBackgroundTask)
@@ -408,12 +409,12 @@ export function ActiveSession() {
 
   // Subscribed once for the app, not per task: the owner of each event is
   // resolved from the page id, so a background task's pages keep reporting.
-  useWorkspaceBrowserEventBridge(!isMobileLayout)
-  useWorkspaceFocusReturn(workspaceEnabled ? activeTabId : null)
+  useWorkspaceBrowserEventBridge(active && !isMobileLayout)
+  useWorkspaceFocusReturn(active && workspaceEnabled ? activeTabId : null)
   useWorkspaceShortcuts({
     sessionId: activeTabId,
     cwd: getSessionTerminalCwd(session) ?? '',
-    enabled: workspaceEnabled,
+    enabled: active && workspaceEnabled,
   })
 
   useEffect(() => {
@@ -877,7 +878,7 @@ export function ActiveSession() {
                   {historyError}
                 </div>
               ) : (
-                <MessageList compact={showRightPanel} mobileLayout={isMobileLayout} />
+                <MessageList sessionId={activeTabId ?? undefined} compact={showRightPanel} mobileLayout={isMobileLayout} />
               )}
             </>
           )}
@@ -897,6 +898,8 @@ export function ActiveSession() {
           ) : null}
 
           <ChatInput
+            sessionId={activeTabId ?? undefined}
+            visible={active}
             variant={isEmpty && !showRightPanel ? 'hero' : 'default'}
             compact={showRightPanel}
           />

desktop/src/stores/chatStore.test.ts

@@ -3,6 +3,7 @@ import type { AgentTaskNotification, UIMessage } from '../types/chat'
 import type { MessageEntry, SessionListItem } from '../types/session'
 import type { SessionHistoryPage } from '../api/sessions'
 import type { SavedProvider } from '../types/provider'
+import type { Tab } from './tabStore'
 import {
   buildMainSessionActivityModel,
   buildSessionActivityModel,
@@ -36,6 +37,7 @@ const {
   connectionStateHandlers,
   sendSubagentMessageMock,
   tabStoreSnapshot,
+  tabStoreListeners,
   providerStoreSnapshot,
 } = vi.hoisted(() => ({
   sendMock: vi.fn(),
@@ -76,7 +78,8 @@ const {
   },
   connectionStateHandlers: new Map<string, (state: 'connecting' | 'connected' | 'reconnecting' | 'disconnected') => void>(),
   sendSubagentMessageMock: vi.fn(async () => ({ ok: true })),
-  tabStoreSnapshot: { tabs: [] as Array<Record<string, unknown>> },
+  tabStoreSnapshot: { tabs: [] as Tab[], activeTabId: null as string | null },
+  tabStoreListeners: new Set<(state: any, previous: any) => void>(),
   providerStoreSnapshot: { providers: [] as SavedProvider[], activeId: null as string | null },
 }))
 
@@ -136,9 +139,14 @@ vi.mock('./tabStore', () => ({
   useTabStore: {
     getState: () => ({
       tabs: tabStoreSnapshot.tabs,
+      activeTabId: tabStoreSnapshot.activeTabId,
       updateTabStatus: updateTabStatusMock,
       updateTabTitle: updateTabTitleMock,
     }),
+    subscribe: (listener: (state: any, previous: any) => void) => {
+      tabStoreListeners.add(listener)
+      return () => tabStoreListeners.delete(listener)
+    },
   },
 }))
 
@@ -14792,7 +14800,9 @@ describe('chatStore history mapping', () => {
     const subagentSessionId = '__subagent__parent-session__tool-agent-1'
     tabStoreSnapshot.tabs = [{
       sessionId: subagentSessionId,
+      title: 'Subagent',
       type: 'subagent',
+      status: 'idle',
       sourceSessionId: 'parent-session',
       subagentToolUseId: 'tool-agent-1',
       subagentTaskId: 'agent-1',
@@ -15873,9 +15883,11 @@ describe('chatStore inactive complete-page retention', () => {
     const { readFileSync } = await import('node:fs')
     imageData = `data:image/png;base64,${readFileSync('src/assets/pets/action-sheet-guide.zh.png').toString('base64')}`
     const { useTabStore } = await import('./tabStore')
+    tabStoreSnapshot.tabs = []
+    tabStoreSnapshot.activeTabId = null
     const tabState = useTabStore.getState()
     activeSessionId = 'image-cache-0'
-    const spy = vi.spyOn(useTabStore, 'getState').mockImplementation(() => ({ ...tabState, activeTabId: activeSessionId }))
+    const spy = vi.spyOn(useTabStore, 'getState').mockImplementation(() => ({ ...tabState, tabs: tabStoreSnapshot.tabs, activeTabId: activeSessionId }))
     restoreTabState = () => spy.mockRestore()
     getMemberBySessionIdMock.mockReturnValue(null)
     vi.mocked(sessionsApi.getFullHistory).mockReset()
@@ -15885,9 +15897,47 @@ describe('chatStore inactive complete-page retention', () => {
 
   afterEach(() => {
     restoreTabState()
+    tabStoreSnapshot.tabs = []
+    tabStoreSnapshot.activeTabId = null
     useChatStore.setState({ ...initialState, sessions: {} })
   })
 
+  it('keeps the last open chat history when a settings or other page takes focus', () => {
+    const sessions = imageSessions()
+    const recentId = 'image-cache-4'
+    for (const [id, session] of Object.entries(sessions)) {
+      useChatStore.getState().markHistoryRowsDurable(id, session.messages)
+    }
+    const sessionTab: Tab = { sessionId: recentId, type: 'session', title: 'Recent', status: 'idle' }
+    const settingsTab: Tab = { sessionId: '__settings__', type: 'settings', title: 'Settings', status: 'idle' }
+    const marketTab: Tab = { sessionId: '__market__', type: 'market', title: 'Market', status: 'idle' }
+    const previous = { tabs: [sessionTab], activeTabId: recentId }
+    const settings = { tabs: [sessionTab, settingsTab], activeTabId: settingsTab.sessionId }
+    tabStoreSnapshot.tabs = settings.tabs
+    activeSessionId = settings.activeTabId
+    for (const listener of tabStoreListeners) listener(settings, previous)
+
+    useChatStore.getState().applyBoundedUpdate(() => ({ sessions }))
+    expect(useChatStore.getState().sessions[recentId]!.messages).toHaveLength(1)
+    expect(useChatStore.getState().sessions['image-cache-0']!.messages).toHaveLength(0)
+
+    const market = { tabs: [...settings.tabs, marketTab], activeTabId: marketTab.sessionId }
+    tabStoreSnapshot.tabs = market.tabs
+    activeSessionId = market.activeTabId
+    for (const listener of tabStoreListeners) listener(market, settings)
+    useChatStore.getState().applyBoundedUpdate(state => ({ sessions: { ...state.sessions } }))
+    expect(useChatStore.getState().sessions[recentId]!.messages).toHaveLength(1)
+
+    const closed = { tabs: [settingsTab, marketTab], activeTabId: marketTab.sessionId }
+    tabStoreSnapshot.tabs = closed.tabs
+    for (const listener of tabStoreListeners) listener(closed, market)
+    for (const [id, session] of Object.entries(sessions)) {
+      useChatStore.getState().markHistoryRowsDurable(id, session.messages)
+    }
+    useChatStore.getState().applyBoundedUpdate(() => ({ sessions }))
+    expect(useChatStore.getState().sessions[recentId]!.messages).toHaveLength(0)
+  })
+
   it('keeps live rows intact while an idle-tab eviction would drop durable pages', () => {
     // Live rows that have not yet been persisted are not eligible for the
     // durable eviction set, so a tab holding them stays mounted whole.

desktop/src/stores/chatStore.ts

@@ -2838,6 +2838,12 @@ function shouldPrewarmSession(sessionId: string): boolean {
 }
 
 export const useChatStore = create<ChatStore>((setState, get) => {
+  let lastViewedSessionId: string | null = null
+  useTabStore.subscribe((tabState, previousTabState) => {
+    if (tabState.activeTabId === previousTabState.activeTabId) return
+    const previousTab = previousTabState.tabs.find(tab => tab.sessionId === previousTabState.activeTabId)
+    if (previousTab?.type === 'session') lastViewedSessionId = previousTab.sessionId
+  })
   const set = (update: Partial<ChatStore> | ((state: ChatStore) => Partial<ChatStore>)) => {
     setState((previous) => {
       const patch = typeof update === 'function' ? update(previous) : update
@@ -2863,6 +2869,11 @@ export const useChatStore = create<ChatStore>((setState, get) => {
       const tabState = useTabStore.getState()
       const activeTab = tabState.tabs.find(tab => tab.sessionId === tabState.activeTabId)
       const activeIds = new Set([tabState.activeTabId, activeTab?.sourceSessionId, activeTab?.workbenchSessionId, activeTab?.teamLeadSessionId])
+      // Keep the chat the user just left warm while a non-chat page is open.
+      // Other idle tabs remain eligible, and closing this tab releases it.
+      if (activeTab?.type !== 'session' && tabState.tabs.some(tab => tab.type === 'session' && tab.sessionId === lastViewedSessionId)) {
+        activeIds.add(lastViewedSessionId)
+      }
       const cacheSizes = new Map(Object.entries(sessions).map(([id, session]) => [id, historyCacheBytes(session)]))
       let retainedBytes = [...cacheSizes.values()].reduce((total, bytes) => total + bytes, 0)
       if (retainedBytes > CHAT_HISTORY_CACHE_BYTES) {