Turn off alternate buffer mode by default. (#13623)

docs/get-started/configuration.md

@@ -240,7 +240,7 @@ their corresponding top-level category object in your `settings.json` file.
 - **`ui.useAlternateBuffer`** (boolean):
   - **Description:** Use an alternate screen buffer for the UI, preserving shell
     history.
-  - **Default:** `true`
+  - **Default:** `false`
   - **Requires restart:** Yes
 
 - **`ui.incrementalRendering`** (boolean):

integration-tests/test-helper.ts

@@ -321,6 +321,9 @@ export class TestRig {
           selectedType: 'gemini-api-key',
         },
       },
+      ui: {
+        useAlternateBuffer: true,
+      },
       model: DEFAULT_GEMINI_MODEL,
       sandbox:
         env['GEMINI_SANDBOX'] !== 'false' ? env['GEMINI_SANDBOX'] : false,

packages/cli/src/config/settingsSchema.ts

@@ -516,7 +516,7 @@ const SETTINGS_SCHEMA = {
         label: 'Use Alternate Screen Buffer',
         category: 'UI',
         requiresRestart: true,
-        default: true,
+        default: false,
         description:
           'Use an alternate screen buffer for the UI, preserving shell history.',
         showInDialog: true,

packages/cli/src/gemini.test.tsx

@@ -509,6 +509,7 @@ describe('startInteractiveUI', () => {
     merged: {
       ui: {
         hideWindowTitle: false,
+        useAlternateBuffer: true,
       },
     },
   } as LoadedSettings;

packages/cli/src/test-utils/render.tsx

@@ -176,7 +176,7 @@ export const renderWithProviders = (
     width,
     mouseEventsEnabled = false,
     config = configProxy as unknown as Config,
-    useAlternateBuffer,
+    useAlternateBuffer = true,
     uiActions,
   }: {
     shellFocus?: boolean;

packages/cli/src/ui/hooks/useAlternateBuffer.ts

@@ -8,7 +8,7 @@ import { useSettings } from '../contexts/SettingsContext.js';
 import type { LoadedSettings } from '../../config/settings.js';
 
 export const isAlternateBufferEnabled = (settings: LoadedSettings): boolean =>
-  settings.merged.ui?.useAlternateBuffer !== false;
+  settings.merged.ui?.useAlternateBuffer === true;
 
 export const useAlternateBuffer = (): boolean => {
   const settings = useSettings();

schemas/settings.schema.json

@@ -292,8 +292,8 @@
         "useAlternateBuffer": {
           "title": "Use Alternate Screen Buffer",
           "description": "Use an alternate screen buffer for the UI, preserving shell history.",
-          "markdownDescription": "Use an alternate screen buffer for the UI, preserving shell history.\n\n- Category: `UI`\n- Requires restart: `yes`\n- Default: `true`",
-          "default": true,
+          "markdownDescription": "Use an alternate screen buffer for the UI, preserving shell history.\n\n- Category: `UI`\n- Requires restart: `yes`\n- Default: `false`",
+          "default": false,
           "type": "boolean"
         },
         "incrementalRendering": {