fix: increase tab max-width and add ellipsis truncation (#166)

- Tab max-width increased from 180px to 360px
- Breadcrumb title now truncates with ellipsis at 40vw max-width

Co-authored-by: Test <test@test.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

design/build-number-status-bar.pen

@@ -0,0 +1,96 @@
+{
+  "children": [
+    {
+      "type": "frame",
+      "id": "build_number_status_bar",
+      "name": "Build Number — Status Bar",
+      "x": 0,
+      "y": 0,
+      "width": 1200,
+      "height": 36,
+      "fill": "$--background",
+      "layout": "horizontal",
+      "gap": 12,
+      "padding": [
+        0,
+        16
+      ],
+      "theme": {
+        "Mode": "Light"
+      },
+      "children": [
+        {
+          "type": "text",
+          "id": "status_vault",
+          "content": "vault-name",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "status_sep1",
+          "content": "|",
+          "fill": "$--border",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "status_build",
+          "content": "b223",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "status_note",
+          "content": "← dynamic build number from package.json, replacing hardcoded v0.4.2",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 11,
+          "fontStyle": "italic"
+        }
+      ]
+    },
+    {
+      "type": "frame",
+      "id": "build_number_fallback",
+      "name": "Build Number — Fallback (no build info)",
+      "x": 0,
+      "y": 60,
+      "width": 400,
+      "height": 36,
+      "fill": "$--background",
+      "layout": "horizontal",
+      "gap": 12,
+      "padding": [
+        0,
+        16
+      ],
+      "theme": {
+        "Mode": "Light"
+      },
+      "children": [
+        {
+          "type": "text",
+          "id": "fallback_build",
+          "content": "b?",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "fallback_note",
+          "content": "← shows b? when build number unavailable",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 11,
+          "fontStyle": "italic"
+        }
+      ]
+    }
+  ]
+}

src-tauri/build.rs

@@ -1,3 +1,14 @@
 fn main() {
+    let count = std::process::Command::new("git")
+        .args(["rev-list", "--count", "HEAD"])
+        .output()
+        .ok()
+        .filter(|o| o.status.success())
+        .and_then(|o| String::from_utf8(o.stdout).ok())
+        .map(|s| s.trim().to_string())
+        .unwrap_or_else(|| "DEV".to_string());
+
+    println!("cargo:rustc-env=BUILD_NUMBER={}", count);
+
     tauri_build::build()
 }

src-tauri/src/lib.rs

@@ -112,6 +112,14 @@ fn git_commit(vault_path: String, message: String) -> Result<String, String> {
     git::git_commit(&vault_path, &message)
 }
 
+#[tauri::command]
+fn get_build_number() -> String {
+    {
+        let n = std::env::var("BUILD_NUMBER").unwrap_or_else(|_| "0".to_string());
+        format!("b{}", n)
+    }
+}
+
 #[tauri::command]
 fn get_last_commit_info(vault_path: String) -> Result<Option<LastCommitInfo>, String> {
     let vault_path = expand_tilde(&vault_path);
@@ -435,6 +443,16 @@ mod tests {
         let result = expand_tilde("/home/~user/path");
         assert_eq!(result, "/home/~user/path");
     }
+
+    #[test]
+    fn get_build_number_returns_prefixed_value() {
+        let result = get_build_number();
+        assert!(
+            result.starts_with('b'),
+            "expected 'b' prefix, got: {}",
+            result
+        );
+    }
 }
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
@@ -498,6 +516,7 @@ pub fn run() {
             get_file_diff,
             get_file_diff_at_commit,
             git_commit,
+            get_build_number,
             get_last_commit_info,
             git_pull,
             git_push,

src/App.tsx

@@ -29,6 +29,7 @@ import { useUpdater } from './hooks/useUpdater'
 import { useNavigationHistory } from './hooks/useNavigationHistory'
 import { useAutoSync } from './hooks/useAutoSync'
 import { useZoom } from './hooks/useZoom'
+import { useBuildNumber } from './hooks/useBuildNumber'
 import { useOnboarding } from './hooks/useOnboarding'
 import { useThemeManager } from './hooks/useThemeManager'
 import { UpdateBanner } from './components/UpdateBanner'
@@ -260,6 +261,7 @@ function App() {
 
   const { setViewMode, sidebarVisible, noteListVisible } = useViewMode()
   const zoom = useZoom()
+  const buildNumber = useBuildNumber()
 
   const commands = useAppCommands({
     activeTabPath: notes.activeTabPath, activeTabPathRef: notes.activeTabPathRef,
@@ -384,7 +386,7 @@ function App() {
         </div>
       </div>
       <UpdateBanner status={updateStatus} actions={updateActions} />
-      <StatusBar noteCount={vault.entries.length} modifiedCount={vault.modifiedFiles.length} vaultPath={vaultSwitcher.vaultPath} vaults={vaultSwitcher.allVaults} onSwitchVault={vaultSwitcher.switchVault} onOpenSettings={dialogs.openSettings} onOpenLocalFolder={vaultSwitcher.handleOpenLocalFolder} onConnectGitHub={dialogs.openGitHubVault} onClickPending={() => setSelection({ kind: 'filter', filter: 'changes' })} hasGitHub={!!settings.github_token} syncStatus={autoSync.syncStatus} lastSyncTime={autoSync.lastSyncTime} conflictCount={autoSync.conflictFiles.length} lastCommitInfo={autoSync.lastCommitInfo} onTriggerSync={autoSync.triggerSync} zoomLevel={zoom.zoomLevel} onZoomReset={zoom.zoomReset} />
+      <StatusBar noteCount={vault.entries.length} modifiedCount={vault.modifiedFiles.length} vaultPath={vaultSwitcher.vaultPath} vaults={vaultSwitcher.allVaults} onSwitchVault={vaultSwitcher.switchVault} onOpenSettings={dialogs.openSettings} onOpenLocalFolder={vaultSwitcher.handleOpenLocalFolder} onConnectGitHub={dialogs.openGitHubVault} onClickPending={() => setSelection({ kind: 'filter', filter: 'changes' })} hasGitHub={!!settings.github_token} syncStatus={autoSync.syncStatus} lastSyncTime={autoSync.lastSyncTime} conflictCount={autoSync.conflictFiles.length} lastCommitInfo={autoSync.lastCommitInfo} onTriggerSync={autoSync.triggerSync} zoomLevel={zoom.zoomLevel} onZoomReset={zoom.zoomReset} buildNumber={buildNumber} />
       <Toast message={toastMessage} onDismiss={() => setToastMessage(null)} />
       <QuickOpenPalette open={dialogs.showQuickOpen} entries={vault.entries} onSelect={notes.handleSelectNote} onClose={dialogs.closeQuickOpen} />
       <CommandPalette open={dialogs.showCommandPalette} commands={commands} onClose={dialogs.closeCommandPalette} />

src/components/BreadcrumbBar.tsx

@@ -156,12 +156,12 @@ export const BreadcrumbBar = memo(function BreadcrumbBar({
       }}
     >
       {/* Left: breadcrumb */}
-      <div className="flex items-center gap-1" style={{ fontSize: 12 }}>
-        <span className="text-muted-foreground">{entry.isA || 'Note'}</span>
-        <span className="text-muted-foreground" style={{ margin: '0 2px' }}>&rsaquo;</span>
-        <span className="font-medium text-foreground">{entry.title}</span>
-        <span className="text-muted-foreground" style={{ margin: '0 4px' }}>&middot;</span>
-        <span className="text-muted-foreground">{wordCount.toLocaleString()} words</span>
+      <div className="flex items-center gap-1 min-w-0 whitespace-nowrap" style={{ fontSize: 12 }}>
+        <span className="shrink-0 text-muted-foreground">{entry.isA || 'Note'}</span>
+        <span className="shrink-0 text-muted-foreground" style={{ margin: '0 2px' }}>&rsaquo;</span>
+        <span className="truncate font-medium text-foreground" style={{ maxWidth: '40vw' }}>{entry.title}</span>
+        <span className="shrink-0 text-muted-foreground" style={{ margin: '0 4px' }}>&middot;</span>
+        <span className="shrink-0 text-muted-foreground">{wordCount.toLocaleString()} words</span>
         {noteStatus === 'pendingSave' && (
           <>
             <span className="text-muted-foreground" style={{ margin: '0 4px' }}>&middot;</span>

src/components/Sidebar.test.tsx

@@ -296,6 +296,39 @@ describe('Sidebar', () => {
     })
   })
 
+  it('expands a collapsed section when clicking its header', () => {
+    render(<Sidebar entries={mockEntries} selection={defaultSelection} onSelect={() => {}} />)
+    // Sections start collapsed — items hidden
+    expect(screen.queryByText('Build Laputa App')).not.toBeInTheDocument()
+    // Click the section header text (not the chevron)
+    fireEvent.click(screen.getByText('Projects'))
+    // Section should now be expanded
+    expect(screen.getByText('Build Laputa App')).toBeInTheDocument()
+  })
+
+  it('collapses an expanded+selected section when clicking its header again', () => {
+    const projectSelection: SidebarSelection = { kind: 'sectionGroup', type: 'Project' }
+    render(<Sidebar entries={mockEntries} selection={projectSelection} onSelect={() => {}} />)
+    // First click expands (starts collapsed) and selects
+    fireEvent.click(screen.getByText('Projects'))
+    expect(screen.getByText('Build Laputa App')).toBeInTheDocument()
+    // Second click: section is expanded + selected → should collapse
+    fireEvent.click(screen.getByText('Projects'))
+    expect(screen.queryByText('Build Laputa App')).not.toBeInTheDocument()
+  })
+
+  it('selects but keeps expanded an unselected expanded section when clicking its header', () => {
+    const onSelect = vi.fn()
+    render(<Sidebar entries={mockEntries} selection={defaultSelection} onSelect={onSelect} />)
+    // Expand via chevron first
+    fireEvent.click(screen.getByLabelText('Expand Projects'))
+    expect(screen.getByText('Build Laputa App')).toBeInTheDocument()
+    // Click the header — section is expanded but not selected → should select and stay expanded
+    fireEvent.click(screen.getByText('Projects'))
+    expect(onSelect).toHaveBeenCalledWith({ kind: 'sectionGroup', type: 'Project' })
+    expect(screen.getByText('Build Laputa App')).toBeInTheDocument()
+  })
+
   it('calls onSelect with sectionGroup for People', () => {
     const onSelect = vi.fn()
     render(<Sidebar entries={mockEntries} selection={defaultSelection} onSelect={onSelect} />)

src/components/SidebarParts.tsx

@@ -156,7 +156,11 @@ function SectionHeader({ label, type, Icon, sectionColor, isCollapsed, isActive,
     <div
       className={cn("group/section flex cursor-pointer select-none items-center justify-between rounded transition-colors", isActive ? "bg-secondary" : "hover:bg-accent")}
       style={{ padding: '6px 8px 6px 6px', borderRadius: 4, gap: 4 }}
-      onClick={onSelect} onContextMenu={onContextMenu}
+      onClick={() => {
+        if (isCollapsed) { onToggle(); onSelect() }
+        else if (isActive) { onToggle() }
+        else { onSelect() }
+      }} onContextMenu={onContextMenu}
     >
       <div className="flex items-center" style={{ gap: 4 }}>
         <div className="flex shrink-0 items-center justify-center text-muted-foreground opacity-0 group-hover/section:opacity-50 hover:!opacity-100 cursor-grab" style={{ width: 16, height: 16 }} {...dragHandleProps} aria-label={`Drag to reorder ${label}`}>

src/components/StatusBar.test.tsx

@@ -25,9 +25,14 @@ describe('StatusBar', () => {
     expect(screen.getByText('9,200 notes')).toBeInTheDocument()
   })
 
-  it('displays version info', () => {
+  it('displays build number when provided', () => {
+    render(<StatusBar noteCount={100} vaultPath="/Users/luca/Laputa" vaults={vaults} onSwitchVault={vi.fn()} buildNumber="b223" />)
+    expect(screen.getByText('b223')).toBeInTheDocument()
+  })
+
+  it('displays fallback build number when not provided', () => {
     render(<StatusBar noteCount={100} vaultPath="/Users/luca/Laputa" vaults={vaults} onSwitchVault={vi.fn()} />)
-    expect(screen.getByText('v0.4.2')).toBeInTheDocument()
+    expect(screen.getByText('b?')).toBeInTheDocument()
   })
 
   it('does not display branch name', () => {

src/components/StatusBar.tsx

@@ -26,6 +26,7 @@ interface StatusBarProps {
   onTriggerSync?: () => void
   zoomLevel?: number
   onZoomReset?: () => void
+  buildNumber?: string
 }
 
 function VaultMenuItem({ vault, isActive, onSelect }: { vault: VaultOption; isActive: boolean; onSelect: () => void }) {
@@ -155,7 +156,7 @@ function CommitBadge({ info }: { info: LastCommitInfo }) {
   )
 }
 
-export function StatusBar({ noteCount, modifiedCount = 0, vaultPath, vaults, onSwitchVault, onOpenSettings, onOpenLocalFolder, onConnectGitHub, onClickPending, hasGitHub, syncStatus = 'idle', lastSyncTime = null, conflictCount = 0, lastCommitInfo, onTriggerSync, zoomLevel = 100, onZoomReset }: StatusBarProps) {
+export function StatusBar({ noteCount, modifiedCount = 0, vaultPath, vaults, onSwitchVault, onOpenSettings, onOpenLocalFolder, onConnectGitHub, onClickPending, hasGitHub, syncStatus = 'idle', lastSyncTime = null, conflictCount = 0, lastCommitInfo, onTriggerSync, zoomLevel = 100, onZoomReset, buildNumber }: StatusBarProps) {
   // Force re-render every 30s to keep relative time label fresh
   const [, setTick] = useState(0)
   useEffect(() => {
@@ -171,7 +172,7 @@ export function StatusBar({ noteCount, modifiedCount = 0, vaultPath, vaults, onS
       <div style={{ display: 'flex', alignItems: 'center', gap: 12 }}>
         <VaultMenu vaults={vaults} vaultPath={vaultPath} onSwitchVault={onSwitchVault} onOpenLocalFolder={onOpenLocalFolder} onConnectGitHub={onConnectGitHub} hasGitHub={hasGitHub} />
         <span style={SEP_STYLE}>|</span>
-        <span style={ICON_STYLE}><Package size={13} />v0.4.2</span>
+        <span style={ICON_STYLE} data-testid="status-build-number"><Package size={13} />{buildNumber ?? 'b?'}</span>
         <span style={SEP_STYLE}>|</span>
         <span
           role="button"

src/components/TabBar.tsx

@@ -219,7 +219,7 @@ function TabItem({ tab, isActive, isEditing, noteStatus, isDragging, showDropBef
       draggable={!isEditing}
       {...dragProps}
       className={cn(
-        "group flex shrink-0 items-center gap-1.5 whitespace-nowrap max-w-[180px] transition-all relative",
+        "group flex shrink-0 items-center gap-1.5 whitespace-nowrap max-w-[360px] transition-all relative",
         isActive ? "text-foreground" : "text-muted-foreground hover:text-secondary-foreground"
       )}
       style={{

src/hooks/useBuildNumber.test.ts

@@ -0,0 +1,25 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { renderHook, waitFor } from '@testing-library/react'
+import { useBuildNumber } from './useBuildNumber'
+
+vi.mock('@tauri-apps/api/core', () => ({ invoke: vi.fn() }))
+vi.mock('../mock-tauri', () => ({
+  isTauri: () => false,
+  mockInvoke: vi.fn().mockResolvedValue('b223'),
+}))
+
+beforeEach(() => { vi.clearAllMocks() })
+
+describe('useBuildNumber', () => {
+  it('returns build number from mock invoke', async () => {
+    const { result } = renderHook(() => useBuildNumber())
+    await waitFor(() => expect(result.current).toBe('b223'))
+  })
+
+  it('returns fallback on error', async () => {
+    const { mockInvoke } = await import('../mock-tauri')
+    vi.mocked(mockInvoke).mockRejectedValueOnce(new Error('fail'))
+    const { result } = renderHook(() => useBuildNumber())
+    await waitFor(() => expect(result.current).toBe('b?'))
+  })
+})

src/hooks/useBuildNumber.ts

@@ -0,0 +1,19 @@
+import { useState, useEffect } from 'react'
+import { invoke } from '@tauri-apps/api/core'
+import { isTauri, mockInvoke } from '../mock-tauri'
+
+function tauriCall<T>(cmd: string): Promise<T> {
+  return isTauri() ? invoke<T>(cmd) : mockInvoke<T>(cmd)
+}
+
+export function useBuildNumber(): string | undefined {
+  const [buildNumber, setBuildNumber] = useState<string>()
+
+  useEffect(() => {
+    tauriCall<string>('get_build_number').then(setBuildNumber).catch(() => {
+      setBuildNumber('b?')
+    })
+  }, [])
+
+  return buildNumber
+}

src/hooks/useEditorTabSwap.test.ts

@@ -1,5 +1,6 @@
-import { describe, it, expect } from 'vitest'
-import { extractEditorBody, getH1TextFromBlocks, replaceTitleInFrontmatter } from './useEditorTabSwap'
+import { describe, it, expect, vi, afterEach } from 'vitest'
+import { renderHook, act } from '@testing-library/react'
+import { extractEditorBody, getH1TextFromBlocks, replaceTitleInFrontmatter, useEditorTabSwap } from './useEditorTabSwap'
 
 describe('extractEditorBody', () => {
   it('strips frontmatter and preserves H1 heading for new note content', () => {
@@ -156,3 +157,150 @@ describe('replaceTitleInFrontmatter', () => {
     expect(replaceTitleInFrontmatter('', 'Title')).toBe('')
   })
 })
+
+describe('useEditorTabSwap scroll position', () => {
+  const blocksA = [{ type: 'paragraph', content: [{ type: 'text', text: 'A' }] }]
+  const blocksB = [{ type: 'paragraph', content: [{ type: 'text', text: 'B' }] }]
+
+  function makeTab(path: string, title: string) {
+    return {
+      entry: { path, title, filename: `${title}.md`, type: 'Note', status: 'Active', aliases: [], isA: '' } as never,
+      content: `---\ntitle: ${title}\n---\n\n# ${title}\n\nBody of ${title}.`,
+    }
+  }
+
+  function makeMockEditor(docRef: { current: unknown[] }) {
+    const mountCallbacks: Array<() => void> = []
+    return {
+      document: docRef.current,
+      get prosemirrorView() { return {} },
+      onMount: (cb: () => void) => { mountCallbacks.push(cb); return () => {} },
+      replaceBlocks: vi.fn((_old, newBlocks) => { docRef.current = newBlocks }),
+      insertBlocks: vi.fn(),
+      blocksToMarkdownLossy: vi.fn(() => ''),
+      blocksToHTMLLossy: vi.fn(() => ''),
+      tryParseMarkdownToBlocks: vi.fn(() => blocksA),
+      _tiptapEditor: { commands: { setContent: vi.fn() } },
+      // Make document getter dynamic
+      _docRef: docRef,
+    }
+  }
+
+  afterEach(() => { vi.restoreAllMocks() })
+
+  it('saves scroll position when switching tabs and restores it when switching back', async () => {
+    const scrollEl = { scrollTop: 0 }
+    vi.spyOn(document, 'querySelector').mockReturnValue(scrollEl as unknown as Element)
+    const rAF = vi.spyOn(window, 'requestAnimationFrame').mockImplementation((cb) => { cb(0); return 0 })
+
+    const docRef = { current: blocksA as unknown[] }
+    const mockEditor = makeMockEditor(docRef)
+    // Override document to be dynamic
+    Object.defineProperty(mockEditor, 'document', { get: () => docRef.current })
+
+    const tabA = makeTab('a.md', 'Note A')
+    const tabB = makeTab('b.md', 'Note B')
+
+    const { rerender } = renderHook(
+      ({ tabs, activeTabPath }) => useEditorTabSwap({
+        tabs,
+        activeTabPath,
+        editor: mockEditor as never,
+      }),
+      { initialProps: { tabs: [tabA, tabB], activeTabPath: 'a.md' } },
+    )
+
+    // Flush the microtask for initial content swap
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    // Simulate scrolling in tab A
+    scrollEl.scrollTop = 350
+
+    // Switch to tab B
+    rerender({ tabs: [tabA, tabB], activeTabPath: 'b.md' })
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    // rAF should have been called to set scroll to 0 (new tab, no cached scroll)
+    expect(rAF).toHaveBeenCalled()
+
+    // Switch back to tab A
+    docRef.current = blocksB // simulate B's content in editor
+    scrollEl.scrollTop = 0 // B is at top
+    rerender({ tabs: [tabA, tabB], activeTabPath: 'a.md' })
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    // The last rAF call should restore A's scroll position (350)
+    const lastRAFCall = rAF.mock.calls[rAF.mock.calls.length - 1]
+    expect(lastRAFCall).toBeDefined()
+    // Execute the callback to verify scrollTop is set
+    scrollEl.scrollTop = 0
+    ;(lastRAFCall[0] as (n: number) => void)(0)
+    expect(scrollEl.scrollTop).toBe(350)
+  })
+
+  it('defaults to scroll top 0 for newly opened tabs', async () => {
+    const scrollEl = { scrollTop: 0 }
+    vi.spyOn(document, 'querySelector').mockReturnValue(scrollEl as unknown as Element)
+    const rAF = vi.spyOn(window, 'requestAnimationFrame').mockImplementation((cb) => { cb(0); return 0 })
+
+    const docRef = { current: blocksA as unknown[] }
+    const mockEditor = makeMockEditor(docRef)
+    Object.defineProperty(mockEditor, 'document', { get: () => docRef.current })
+
+    const tabA = makeTab('a.md', 'Note A')
+
+    renderHook(
+      ({ tabs, activeTabPath }) => useEditorTabSwap({
+        tabs,
+        activeTabPath,
+        editor: mockEditor as never,
+      }),
+      { initialProps: { tabs: [tabA], activeTabPath: 'a.md' } },
+    )
+
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    // For a fresh tab, scroll should go to 0
+    expect(rAF).toHaveBeenCalled()
+    expect(scrollEl.scrollTop).toBe(0)
+  })
+
+  it('cleans up scroll cache when a tab is closed', async () => {
+    const scrollEl = { scrollTop: 100 }
+    vi.spyOn(document, 'querySelector').mockReturnValue(scrollEl as unknown as Element)
+    vi.spyOn(window, 'requestAnimationFrame').mockImplementation((cb) => { cb(0); return 0 })
+
+    const docRef = { current: blocksA as unknown[] }
+    const mockEditor = makeMockEditor(docRef)
+    Object.defineProperty(mockEditor, 'document', { get: () => docRef.current })
+
+    const tabA = makeTab('a.md', 'Note A')
+    const tabB = makeTab('b.md', 'Note B')
+
+    const { rerender } = renderHook(
+      ({ tabs, activeTabPath }) => useEditorTabSwap({
+        tabs,
+        activeTabPath,
+        editor: mockEditor as never,
+      }),
+      { initialProps: { tabs: [tabA, tabB], activeTabPath: 'a.md' } },
+    )
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    // Switch to B (caches A's scroll at 100)
+    rerender({ tabs: [tabA, tabB], activeTabPath: 'b.md' })
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    // Close tab A (only tab B remains)
+    rerender({ tabs: [tabB], activeTabPath: 'b.md' })
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    // Reopen tab A — should start at scroll 0, not the cached 100
+    const tabANew = makeTab('a.md', 'Note A')
+    scrollEl.scrollTop = 0
+    rerender({ tabs: [tabB, tabANew], activeTabPath: 'a.md' })
+    await act(() => new Promise(r => setTimeout(r, 0)))
+
+    expect(scrollEl.scrollTop).toBe(0)
+  })
+})

src/hooks/useEditorTabSwap.ts

@@ -61,9 +61,9 @@ export function replaceTitleInFrontmatter(frontmatter: string, newTitle: string)
  * Returns `handleEditorChange`, the onChange callback for SingleEditorView.
  */
 export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange, onH1Change, syncActiveRef }: UseEditorTabSwapOptions) {
-  // Cache parsed blocks per tab path for instant switching
+  // Cache parsed blocks + scroll position per tab path for instant switching
   // eslint-disable-next-line @typescript-eslint/no-explicit-any -- BlockNote block arrays
-  const tabCacheRef = useRef<Map<string, any[]>>(new Map())
+  const tabCacheRef = useRef<Map<string, { blocks: any[]; scrollTop: number }>>(new Map())
   const prevActivePathRef = useRef<string | null>(null)
   const editorMountedRef = useRef(false)
   const pendingSwapRef = useRef<(() => void) | null>(null)
@@ -136,9 +136,13 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
     const prevPath = prevActivePathRef.current
     const pathChanged = prevPath !== activeTabPath
 
-    // Save current editor state for the tab we're leaving
+    // Save current editor state + scroll position for the tab we're leaving
     if (prevPath && pathChanged && editorMountedRef.current) {
-      cache.set(prevPath, editor.document)
+      const scrollEl = document.querySelector('.editor__blocknote-container')
+      cache.set(prevPath, {
+        blocks: editor.document,
+        scrollTop: scrollEl?.scrollTop ?? 0,
+      })
     }
     prevActivePathRef.current = activeTabPath
 
@@ -148,7 +152,11 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
     // the editor already shows the user's edits.
     if (!pathChanged) {
       if (activeTabPath && editorMountedRef.current) {
-        cache.set(activeTabPath, editor.document)
+        const scrollEl = document.querySelector('.editor__blocknote-container')
+        cache.set(activeTabPath, {
+          blocks: editor.document,
+          scrollTop: scrollEl?.scrollTop ?? 0,
+        })
       }
       return
     }
@@ -159,7 +167,7 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
     if (!tab) return
 
     // eslint-disable-next-line @typescript-eslint/no-explicit-any -- BlockNote's PartialBlock generic is extremely complex
-    const applyBlocks = (blocks: any[]) => {
+    const applyBlocks = (blocks: any[], scrollTop = 0) => {
       suppressChangeRef.current = true
       try {
         const current = editor.document
@@ -181,6 +189,11 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
         // finishes its internal state updates from the content swap
         queueMicrotask(() => { suppressChangeRef.current = false })
       }
+      // Restore scroll position after layout updates from the content swap
+      requestAnimationFrame(() => {
+        const scrollEl = document.querySelector('.editor__blocknote-container')
+        if (scrollEl) scrollEl.scrollTop = scrollTop
+      })
     }
 
     const targetPath = activeTabPath
@@ -190,7 +203,8 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
       if (prevActivePathRef.current !== targetPath) return
 
       if (cache.has(targetPath)) {
-        applyBlocks(cache.get(targetPath)!)
+        const cached = cache.get(targetPath)!
+        applyBlocks(cached.blocks, cached.scrollTop)
         return
       }
 
@@ -202,7 +216,7 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
       // so the editor is immediately interactive.
       if (!preprocessed.trim()) {
         const emptyDoc = [{ type: 'paragraph', content: [] }]
-        cache.set(targetPath, emptyDoc)
+        cache.set(targetPath, { blocks: emptyDoc, scrollTop: 0 })
         applyBlocks(emptyDoc)
         return
       }
@@ -215,7 +229,7 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
           { type: 'heading', props: { level: 1, textColor: 'default', backgroundColor: 'default', textAlignment: 'left' }, content: [{ type: 'text', text: h1OnlyMatch[1], styles: {} }], children: [] },
           { type: 'paragraph', content: [], children: [] },
         ]
-        cache.set(targetPath, h1Doc)
+        cache.set(targetPath, { blocks: h1Doc, scrollTop: 0 })
         applyBlocks(h1Doc)
         return
       }
@@ -228,7 +242,7 @@ export function useEditorTabSwap({ tabs, activeTabPath, editor, onContentChange,
           const withWikilinks = injectWikilinks(blocks)
           // Only cache non-empty results to avoid poisoning the cache
           if (withWikilinks.length > 0) {
-            cache.set(targetPath, withWikilinks)
+            cache.set(targetPath, { blocks: withWikilinks, scrollTop: 0 })
           }
           applyBlocks(withWikilinks)
         }

src/mock-tauri/mock-handlers.ts

@@ -162,6 +162,7 @@ export const mockHandlers: Record<string, (args: any) => any> = {
     mockSavedSinceCommit.clear()
     return `[main abc1234] ${args.message}\n ${count} files changed`
   },
+  get_build_number: () => 'bDEV',
   get_last_commit_info: (): LastCommitInfo => ({ shortHash: 'a1b2c3d', commitUrl: 'https://github.com/lucaong/laputa-vault/commit/a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0' }),
   git_pull: (): GitPullResult => ({ status: 'up_to_date', message: 'Already up to date', updatedFiles: [], conflictFiles: [] }),
   git_push: () => 'Everything up-to-date',