diff --git a/desktop/src/components/layout/Sidebar.test.tsx b/desktop/src/components/layout/Sidebar.test.tsx
index f380c64a..fd612e55 100644
--- a/desktop/src/components/layout/Sidebar.test.tsx
+++ b/desktop/src/components/layout/Sidebar.test.tsx
@@ -17,6 +17,7 @@ vi.mock('../../i18n', () => ({
       'sidebar.noMatching': 'No matching sessions',
       'sidebar.sessionListFailed': 'Session list failed',
       'common.retry': 'Retry',
+      'common.loading': 'Loading...',
       'common.cancel': 'Cancel',
       'common.delete': 'Delete',
       'common.rename': 'Rename',
@@ -201,4 +202,13 @@ describe('Sidebar', () => {
 
     expect(screen.getByTestId('sidebar-session-list-section')).toHaveClass('flex', 'flex-1', 'min-h-0', 'flex-col')
   })
+
+  it('shows a loading state instead of an empty session list while initial fetch is pending', () => {
+    useSessionStore.setState({ isLoading: true, sessions: [] })
+
+    render(<Sidebar />)
+
+    expect(screen.getByText('Loading...')).toBeInTheDocument()
+    expect(screen.queryByText('No sessions')).not.toBeInTheDocument()
+  })
 })
diff --git a/desktop/src/components/layout/Sidebar.tsx b/desktop/src/components/layout/Sidebar.tsx
index c0add799..c8433899 100644
--- a/desktop/src/components/layout/Sidebar.tsx
+++ b/desktop/src/components/layout/Sidebar.tsx
@@ -18,6 +18,7 @@ const TIME_GROUP_ORDER: TimeGroup[] = ['today', 'yesterday', 'last7days', 'last3
 export function Sidebar() {
   const sessions = useSessionStore((s) => s.sessions)
   const selectedProjects = useSessionStore((s) => s.selectedProjects)
+  const isLoading = useSessionStore((s) => s.isLoading)
   const error = useSessionStore((s) => s.error)
   const fetchSessions = useSessionStore((s) => s.fetchSessions)
   const deleteSession = useSessionStore((s) => s.deleteSession)
@@ -63,6 +64,7 @@ export function Sidebar() {
   }, [sessions, selectedProjects, searchQuery])
 
   const timeGroups = useMemo(() => groupByTime(filteredSessions), [filteredSessions])
+  const showInitialLoading = isLoading && sessions.length === 0
 
   const handleContextMenu = useCallback((e: React.MouseEvent, id: string) => {
     e.preventDefault()
@@ -245,7 +247,11 @@ export function Sidebar() {
                   </button>
                 </div>
               )}
-              {filteredSessions.length === 0 && (
+              {showInitialLoading ? (
+                <div className="px-3 py-4 text-center text-xs text-[var(--color-text-tertiary)]">
+                  {t('common.loading')}
+                </div>
+              ) : filteredSessions.length === 0 && (
                 <div className="px-3 py-4 text-center text-xs text-[var(--color-text-tertiary)]">
                   {searchQuery ? t('sidebar.noMatching') : t('sidebar.noSessions')}
                 </div>
diff --git a/desktop/src/components/layout/TabBar.tsx b/desktop/src/components/layout/TabBar.tsx
index 1e92a828..4b52bbdc 100644
--- a/desktop/src/components/layout/TabBar.tsx
+++ b/desktop/src/components/layout/TabBar.tsx
@@ -411,7 +411,7 @@ const TabItem = forwardRef<HTMLDivElement, {
         ${isDragging ? 'z-20 cursor-grabbing' : 'cursor-grab'}
         transition-[background-color,box-shadow,opacity,transform] duration-150 ease-out
         ${isActive
-          ? 'bg-[var(--color-surface)]'
+          ? 'bg-[var(--color-surface)] shadow-[inset_0_-2px_0_var(--color-brand)]'
           : 'bg-transparent hover:bg-[var(--color-surface-hover)]'
         }
         ${isDragging ? 'opacity-95 shadow-[0_10px_24px_rgba(0,0,0,0.18)] ring-1 ring-[var(--color-border)]' : ''}
diff --git a/src/server/__tests__/conversations.test.ts b/src/server/__tests__/conversations.test.ts
index 9632588d..4d354fe7 100644
--- a/src/server/__tests__/conversations.test.ts
+++ b/src/server/__tests__/conversations.test.ts
@@ -10,7 +10,7 @@ import * as fs from 'fs/promises'
 import * as path from 'path'
 import * as os from 'os'
 import { fileURLToPath } from 'node:url'
-import { ConversationService, conversationService } from '../services/conversationService.js'
+import { ConversationService, ConversationStartupError, conversationService } from '../services/conversationService.js'
 import { SessionService } from '../services/sessionService.js'
 import { ProviderService } from '../services/providerService.js'
 
@@ -30,6 +30,21 @@ describe('ConversationService', () => {
     expect(svc.getActiveSessions()).toEqual([])
   })
 
+  it('should block startup after a session is deleted during prewarm', async () => {
+    const svc = new ConversationService()
+    const sid = crypto.randomUUID()
+
+    svc.markSessionDeleted(sid)
+
+    try {
+      await svc.startSession(sid, process.cwd(), 'ws://127.0.0.1:1/sdk/test')
+      throw new Error('expected startSession to reject')
+    } catch (error) {
+      expect(error).toBeInstanceOf(ConversationStartupError)
+      expect((error as ConversationStartupError).code).toBe('SESSION_DELETED')
+    }
+  })
+
   it('should return false when sending message to non-existent session', async () => {
     const svc = new ConversationService()
     const result = await svc.sendMessage('no-such-session', 'hello')
diff --git a/src/server/__tests__/sessions.test.ts b/src/server/__tests__/sessions.test.ts
index 7b66c2af..e3e208d6 100644
--- a/src/server/__tests__/sessions.test.ts
+++ b/src/server/__tests__/sessions.test.ts
@@ -374,6 +374,34 @@ describe('SessionService', () => {
     expect(page2.sessions).toHaveLength(1)
   })
 
+  it('should only parse the requested page when listing many sessions', async () => {
+    for (let i = 0; i < 12; i++) {
+      const id = `1000000${i.toString(16)}-bbbb-cccc-dddd-eeeeeeeeeeee`
+      const filePath = await writeSessionFile('-tmp-many-sessions', id, [
+        makeSnapshotEntry(),
+        makeUserEntry(`Message ${i}`),
+      ])
+      const mtime = new Date(Date.now() - i * 1000)
+      await fs.utimes(filePath, mtime, mtime)
+    }
+
+    const serviceWithSpy = service as unknown as {
+      readJsonlFile: (...args: unknown[]) => Promise<unknown>
+    }
+    const originalReadJsonlFile = serviceWithSpy.readJsonlFile.bind(service)
+    let readCount = 0
+    serviceWithSpy.readJsonlFile = async (...args) => {
+      readCount += 1
+      return originalReadJsonlFile(...args)
+    }
+
+    const result = await service.listSessions({ limit: 3, offset: 0 })
+
+    expect(result.total).toBe(12)
+    expect(result.sessions).toHaveLength(3)
+    expect(readCount).toBe(3)
+  })
+
   it('should filter sessions by project', async () => {
     const id1 = 'aaaaaaaa-1111-cccc-dddd-eeeeeeeeeeee'
     const id2 = 'aaaaaaaa-2222-cccc-dddd-eeeeeeeeeeee'
diff --git a/src/server/__tests__/title-service.test.ts b/src/server/__tests__/title-service.test.ts
index f01d2670..30893fb9 100644
--- a/src/server/__tests__/title-service.test.ts
+++ b/src/server/__tests__/title-service.test.ts
@@ -2,7 +2,8 @@ import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
 import * as fs from 'fs/promises'
 import * as os from 'os'
 import * as path from 'path'
-import { generateTitle } from '../services/titleService.js'
+import { generateTitle, saveAiTitle } from '../services/titleService.js'
+import { sessionService } from '../services/sessionService.js'
 
 describe('titleService', () => {
   let tmpDir: string
@@ -68,6 +69,21 @@ describe('titleService', () => {
       server.stop(true)
     }
   })
+
+  test('does not persist automatic titles over a user custom title', async () => {
+    const { sessionId } = await sessionService.createSession(os.tmpdir())
+    await sessionService.renameSession(sessionId, 'My fixed name')
+
+    await expect(saveAiTitle(sessionId, 'Automatic topic')).resolves.toBe(false)
+
+    const detail = await sessionService.getSession(sessionId)
+    expect(detail?.title).toBe('My fixed name')
+
+    const found = await sessionService.findSessionFile(sessionId)
+    expect(found).not.toBeNull()
+    const content = await fs.readFile(found!.filePath, 'utf-8')
+    expect(content).not.toContain('"type":"ai-title"')
+  })
 })
 
 function restoreEnv(key: string, value: string | undefined) {
diff --git a/src/server/api/sessions.ts b/src/server/api/sessions.ts
index 94f3d6c8..324a9cbd 100644
--- a/src/server/api/sessions.ts
+++ b/src/server/api/sessions.ts
@@ -308,6 +308,7 @@ function isSessionNotFoundError(error: unknown): error is Error {
 }
 
 async function deleteSession(sessionId: string): Promise<Response> {
+  conversationService.markSessionDeleted(sessionId)
   await sessionService.deleteSession(sessionId)
   return Response.json({ ok: true })
 }
diff --git a/src/server/services/conversationService.ts b/src/server/services/conversationService.ts
index 4c55d4e8..88dff761 100644
--- a/src/server/services/conversationService.ts
+++ b/src/server/services/conversationService.ts
@@ -61,7 +61,8 @@ export class ConversationStartupError extends Error {
       | 'CLI_AUTH_REQUIRED'
       | 'CLI_SESSION_CONFLICT'
       | 'CLI_START_FAILED'
-      | 'CLI_SPAWN_FAILED',
+      | 'CLI_SPAWN_FAILED'
+      | 'SESSION_DELETED',
     readonly retryable = false,
   ) {
     super(message)
@@ -71,6 +72,7 @@ export class ConversationStartupError extends Error {
 
 export class ConversationService {
   private sessions = new Map<string, SessionProcess>()
+  private deletedSessions = new Set<string>()
   private providerService = new ProviderService()
 
   private buildSessionCliArgs(
@@ -106,6 +108,12 @@ export class ConversationService {
     sdkUrl: string,
     options?: SessionStartOptions,
   ): Promise<void> {
+    if (this.deletedSessions.has(sessionId)) {
+      throw new ConversationStartupError(
+        `Session was deleted before startup completed: ${sessionId}`,
+        'SESSION_DELETED',
+      )
+    }
     if (this.sessions.has(sessionId)) return
 
     const launchInfo = await sessionService.getSessionLaunchInfo(sessionId)
@@ -113,6 +121,13 @@ export class ConversationService {
     const shouldReplacePlaceholder =
       !!launchInfo && launchInfo.transcriptMessageCount === 0
 
+    if (this.deletedSessions.has(sessionId)) {
+      throw new ConversationStartupError(
+        `Session was deleted before startup completed: ${sessionId}`,
+        'SESSION_DELETED',
+      )
+    }
+
     if (shouldReplacePlaceholder) {
       await sessionService.deleteSessionFile(sessionId)
     }
@@ -479,6 +494,11 @@ export class ConversationService {
     }
   }
 
+  markSessionDeleted(sessionId: string): void {
+    this.deletedSessions.add(sessionId)
+    this.stopSession(sessionId)
+  }
+
   getActiveSessions(): string[] {
     return Array.from(this.sessions.keys())
   }
diff --git a/src/server/services/sessionService.ts b/src/server/services/sessionService.ts
index aa5ee911..6abab2cd 100644
--- a/src/server/services/sessionService.ts
+++ b/src/server/services/sessionService.ts
@@ -991,13 +991,27 @@ export class SessionService {
     offset?: number
   }): Promise<{ sessions: SessionListItem[]; total: number }> {
     const sessionFiles = await this.discoverSessionFiles(options?.project)
+    const filesWithStats = (await Promise.all(sessionFiles.map(async (sessionFile) => {
+      try {
+        return {
+          ...sessionFile,
+          stat: await fs.stat(sessionFile.filePath),
+        }
+      } catch {
+        return null
+      }
+    }))).filter((item): item is NonNullable<typeof item> => item !== null)
+
+    filesWithStats.sort((a, b) => b.stat.mtime.getTime() - a.stat.mtime.getTime())
+
+    const total = filesWithStats.length
+    const offset = options?.offset ?? 0
+    const limit = options?.limit ?? 50
+    const paginatedFiles = filesWithStats.slice(offset, offset + limit)
 
     // Build session list items with metadata from file stats & first entries
-    const items: SessionListItem[] = []
-
-    for (const { filePath, projectDir, sessionId } of sessionFiles) {
+    const items = (await Promise.all(paginatedFiles.map(async ({ filePath, projectDir, sessionId, stat }) => {
       try {
-        const stat = await fs.stat(filePath)
         const entries = await this.readJsonlFile(filePath)
         const workDir = this.resolveWorkDirFromEntries(entries, projectDir)
         const workDirExists = await this.pathExists(workDir)
@@ -1018,7 +1032,7 @@ export class SessionService {
           }
         }
 
-        items.push({
+        return {
           id: sessionId,
           title,
           createdAt,
@@ -1027,21 +1041,14 @@ export class SessionService {
           projectPath: projectDir,
           workDir,
           workDirExists,
-        })
+        }
       } catch {
         // Skip unreadable files
+        return null
       }
-    }
+    }))).filter((item): item is SessionListItem => item !== null)
 
-    // Sort by modifiedAt descending (most recent first)
-    items.sort((a, b) => new Date(b.modifiedAt).getTime() - new Date(a.modifiedAt).getTime())
-
-    const total = items.length
-    const offset = options?.offset ?? 0
-    const limit = options?.limit ?? 50
-    const paginated = items.slice(offset, offset + limit)
-
-    return { sessions: paginated, total }
+    return { sessions: items, total }
   }
 
   /**
@@ -1212,6 +1219,20 @@ export class SessionService {
     })
   }
 
+  async getCustomTitle(sessionId: string): Promise<string | null> {
+    const found = await this.findSessionFile(sessionId)
+    if (!found) return null
+
+    const entries = await this.readJsonlFile(found.filePath)
+    let customTitle: string | null = null
+    for (const entry of entries) {
+      if (entry.type === 'custom-title' && typeof entry.customTitle === 'string' && entry.customTitle.trim()) {
+        customTitle = entry.customTitle
+      }
+    }
+    return customTitle
+  }
+
   /**
    * Get the actual working directory for a session.
    * First checks for stored session-meta entry, then falls back to desanitizePath.
diff --git a/src/server/services/titleService.ts b/src/server/services/titleService.ts
index fd319ae4..c4cce896 100644
--- a/src/server/services/titleService.ts
+++ b/src/server/services/titleService.ts
@@ -123,7 +123,13 @@ async function shouldDisableThinkingForTitle(presetId: string): Promise<boolean>
 
 /**
  * Persist an AI-generated title to the session's JSONL file.
+ * Returns false when a user custom title exists, because custom titles are
+ * intentional and must not be replaced by automatic title refreshes.
  */
-export async function saveAiTitle(sessionId: string, title: string): Promise<void> {
+export async function saveAiTitle(sessionId: string, title: string): Promise<boolean> {
+  if (await sessionService.getCustomTitle(sessionId)) {
+    return false
+  }
   await sessionService.appendAiTitle(sessionId, title)
+  return true
 }
diff --git a/src/server/ws/handler.ts b/src/server/ws/handler.ts
index 5656e809..6c1f623e 100644
--- a/src/server/ws/handler.ts
+++ b/src/server/ws/handler.ts
@@ -278,7 +278,12 @@ async function handleUserMessage(
   // Track user message for title generation
   let titleState = sessionTitleState.get(sessionId)
   if (!titleState) {
-    titleState = { userMessageCount: 0, hasCustomTitle: false, firstUserMessage: '', allUserMessages: [] }
+    titleState = {
+      userMessageCount: 0,
+      hasCustomTitle: !!(await sessionService.getCustomTitle(sessionId)),
+      firstUserMessage: '',
+      allUserMessages: [],
+    }
     sessionTitleState.set(sessionId, titleState)
   }
   titleState.userMessageCount++
@@ -606,7 +611,11 @@ function triggerTitleGeneration(ws: ServerWebSocket<WebSocketData>, sessionId: s
       if (count === 1) {
         const placeholder = deriveTitle(text)
         if (placeholder) {
-          await saveAiTitle(sessionId, placeholder)
+          const saved = await saveAiTitle(sessionId, placeholder)
+          if (!saved) {
+            state.hasCustomTitle = true
+            return
+          }
           sendMessage(ws, { type: 'session_title_updated', sessionId, title: placeholder })
         }
       }
@@ -614,7 +623,11 @@ function triggerTitleGeneration(ws: ServerWebSocket<WebSocketData>, sessionId: s
       // Stage 2: AI-generated title
       const aiTitle = await generateTitle(text, runtimeProviderId)
       if (aiTitle) {
-        await saveAiTitle(sessionId, aiTitle)
+        const saved = await saveAiTitle(sessionId, aiTitle)
+        if (!saved) {
+          state.hasCustomTitle = true
+          return
+        }
         sendMessage(ws, { type: 'session_title_updated', sessionId, title: aiTitle })
       }
     } catch (err) {