diff --git a/docs/wiki/Keyboard-Shortcuts.md b/docs/wiki/Keyboard-Shortcuts.md
index 66212940..d4d54c46 100644
--- a/docs/wiki/Keyboard-Shortcuts.md
+++ b/docs/wiki/Keyboard-Shortcuts.md
@@ -10,7 +10,6 @@ Press `Ctrl+?` in the app for the same list in a floating overlay.
 | ------------------------------- | --------------------------------------------------------------- |
 | `Ctrl+K` (also `Cmd+K`, `Alt+K`)| Find an open session or start a new one.                         |
 | `Ctrl+Tab`                      | Next session.                                                    |
-| `Alt+←` / `Alt+→`               | File Viewer window: back / forward between previewed files.      |
 | `Alt+[` / `Alt+]`               | Previous / next tab.                                             |
 | `Alt+1` to `Alt+9`              | Switch to tab N. Physical keys, so macOS Option layouts work.    |
 | `Ctrl+Shift+{` / `Ctrl+Shift+}` | Move the active tab left / right.                                |
@@ -58,11 +57,12 @@ default. See [Tile Grid](Tile-Grid).
 
 ## Everything else
 
-| Shortcut       | Action                          |
-| -------------- | ------------------------------- |
-| `Ctrl+Shift+V` | Toggle voice input.              |
-| `Ctrl+?`       | Shortcut reference overlay.      |
-| `Escape`       | Close panels and modals.         |
+| Shortcut          | Action                                                       |
+| ----------------- | ------------------------------------------------------------ |
+| `Ctrl+Shift+V`    | Toggle voice input.                                          |
+| `Ctrl+?`          | Shortcut reference overlay.                                  |
+| `Escape`          | Close panels and modals.                                     |
+| `Alt+←` / `Alt+→` | File Viewer window: back / forward between previewed files.  |
 
 ## Rebinding
 
diff --git a/src/web/public/app.js b/src/web/public/app.js
index 62716497..29077b53 100644
--- a/src/web/public/app.js
+++ b/src/web/public/app.js
@@ -685,6 +685,14 @@ const DEFAULT_SHORTCUTS = [
     label: 'Close Panels',
     displayBindings: ['Escape'],
   },
+  // Handled by the File Viewer's own capture-phase listener while it is open
+  // (_bindFilePreviewChrome, panels-ui.js), never through the registry.
+  {
+    id: 'file-preview-history',
+    group: 'Panels',
+    label: 'File Viewer Back / Forward',
+    displayBindings: ['Alt/Option+ArrowLeft', 'Alt/Option+ArrowRight'],
+  },
 ];
 
 
diff --git a/src/web/public/i18n.js b/src/web/public/i18n.js
index 1dc592fa..d7951087 100644
--- a/src/web/public/i18n.js
+++ b/src/web/public/i18n.js
@@ -1044,7 +1044,6 @@
     'Back to the previous file': '返回上一个文件',
     'Forward to the next file': '前进到下一个文件',
     Expand: '展开',
-    'Restore size': '恢复大小',
     'Drag to resize': '拖动以调整大小',
     'Rendered markdown': '渲染 Markdown',
     'Line numbers': '行号',
@@ -1242,6 +1241,7 @@
     'Voice input (Ctrl+Shift+V)': '语音输入（Ctrl+Shift+V）',
     'Insert Newline': '插入换行',
     'Close Panels': '关闭面板',
+    'File Viewer Back / Forward': '文件查看器后退 / 前进',
     'Previous / Next Session': '上一个 / 下一个会话',
     'Next Session': '下一个会话',
     'Previous Session': '上一个会话',
diff --git a/src/web/public/index.html b/src/web/public/index.html
index 46ac8247..ceda80f3 100644
--- a/src/web/public/index.html
+++ b/src/web/public/index.html
@@ -926,6 +926,7 @@
               <div><kbd>Ctrl</kbd>+<kbd>?</kbd></div><div>Show Shortcuts</div>
               <div><kbd>Alt/Option</kbd>+<kbd>?</kbd></div><div>Show Shortcuts</div>
               <div><kbd>Escape</kbd></div><div>Close Panels</div>
+              <div><kbd>Alt/Option</kbd>+<kbd>ArrowLeft</kbd> / <kbd>Alt/Option</kbd>+<kbd>ArrowRight</kbd></div><div>File Viewer Back / Forward</div>
             </div>
           </section>
         </div>
diff --git a/src/web/public/styles.css b/src/web/public/styles.css
index 4f3b926e..aca188de 100644
--- a/src/web/public/styles.css
+++ b/src/web/public/styles.css
@@ -12251,7 +12251,8 @@ html:is([data-skin="paper-gray"], [data-skin="solarized-light"], [data-skin="cat
 
 /* Corner grip (panels-ui.js _bindFilePreviewResize). The window is centred, so a
    drag moves both edges: the handler doubles the pointer delta to keep the corner
-   under the pointer. Touch devices use the Expand button instead. */
+   under the pointer. Only phones hide it (with Expand, mobile.css under 600px), since
+   the window is full screen there; tablets show and use it. */
 .file-preview-resize {
   position: absolute;
   right: 0;
diff --git a/test/help-modal-shortcuts.test.ts b/test/help-modal-shortcuts.test.ts
index 20e54c94..25e9c0fd 100644
--- a/test/help-modal-shortcuts.test.ts
+++ b/test/help-modal-shortcuts.test.ts
@@ -51,6 +51,7 @@ describe('help modal shortcuts', () => {
     expect(helpModal).not.toMatch(/Ctrl<\/kbd>\s*\+\s*<kbd>\/<\/kbd>.*?Show Shortcuts/i);
     expectShortcut(helpModal, ['Ctrl', 'Shift', 'V'], 'Voice Input');
     expectShortcut(helpModal, ['Escape'], 'Close Panels');
+    expectShortcut(helpModal, ['Alt/Option', 'ArrowLeft'], 'File Viewer Back / Forward');
   });
 
   it('documents the tile grid chords', () => {