fix(cli): stop resize repaint from causing scroll storm

eslint.legacy-filenames.mjs

@@ -563,7 +563,6 @@ export const legacyFilenames = [
   'toolResultDisplayCompaction',
   'usageHistoryService',
   'useMcpApproval',
-  'useResizeSettleRepaint',
   'useStatsDialog',
   'useTeamInProcess',
   'userMemory',

packages/cli/src/ui/AppContainer.test.tsx

@@ -32,7 +32,7 @@ import {
   type Mock,
 } from 'vitest';
 import { render, cleanup } from 'ink-testing-library';
-import { useContext, useState, act } from 'react';
+import { useContext, useState, useReducer, useEffect, act } from 'react';
 import {
   AppContainer,
   dedupeNewestFirst,
@@ -1092,13 +1092,10 @@ describe('AppContainer State Management', () => {
       expect(capturedUIState.useTerminalBuffer).toBe(true);
     });
 
-    // #4891 changed the resize contract: width changes now trigger ONE full
-    // clearTerminal after RESIZE_REPAINT_SETTLE_MS (trailing-edge debounce),
-    // instead of never (#3967) or per-event (pre-#3967). This test pins the
-    // synchronous half: no immediate clear during the burst. The settle-time
-    // half is not observable here — ink-testing-library's rerender does not
-    // flush update-time passive effects — and is covered by
-    // useResizeSettleRepaint.test.ts.
+    // Resize no longer triggers a clearTerminal or history remount (#8004).
+    // The old settle → refreshStatic path caused a scroll storm; the dynamic
+    // region now re-renders via useTerminalSize alone. This test pins that
+    // no synchronous clear fires during a width change.
     it('does not clear the terminal synchronously on width change', () => {
       vi.spyOn(mockConfig, 'initialize').mockResolvedValue(undefined);
       mockedUseTerminalSize.mockReturnValue({ columns: 80, rows: 24 });
@@ -1127,6 +1124,64 @@ describe('AppContainer State Management', () => {
       );
     });
 
+    it('does not repaint static history after a resize settles (#8004)', () => {
+      vi.useFakeTimers();
+      vi.spyOn(mockConfig, 'initialize').mockResolvedValue(undefined);
+      // measureElement must return a real measurement; a bare vi.fn() returns
+      // undefined, the controlsHeight layout effect throws on .height, and
+      // ink's ErrorBoundary silently unmounts the tree — making every
+      // post-mount assertion vacuous.
+      (measureElement as Mock).mockReturnValue({ width: 80, height: 2 });
+
+      // Deliver width changes to the SAME mounted instance. rerender() from
+      // ink-testing-library remounts the tree (ErrorBoundary issue above),
+      // re-seeding useRef(terminalWidth) so a settle debounce never fires.
+      let columns = 80;
+      const resizeListeners = new Set<() => void>();
+      mockedUseTerminalSize.mockImplementation(() => {
+        const [, force] = useReducer((x: number) => x + 1, 0);
+        useEffect(() => {
+          resizeListeners.add(force);
+          return () => {
+            resizeListeners.delete(force);
+          };
+        }, []);
+        return { columns, rows: 24 };
+      });
+
+      render(
+        <AppContainer
+          config={mockConfig}
+          settings={mockSettings}
+          version="1.0.0"
+          initializationResult={mockInitResult}
+        />,
+      );
+
+      // Liveness control: fails if the ErrorBoundary unmounted the tree.
+      expect(resizeListeners.size).toBeGreaterThan(0);
+      const remountKeyBefore = capturedUIState.historyRemountKey;
+      mockStdout.write.mockClear();
+
+      act(() => {
+        columns = 100;
+        for (const notify of resizeListeners) notify();
+      });
+
+      // Advance well past the old RESIZE_REPAINT_SETTLE_MS (200ms) debounce.
+      act(() => {
+        vi.advanceTimersByTime(500);
+      });
+
+      expect(mockStdout.write).not.toHaveBeenCalledWith(
+        ansiEscapes.clearTerminal,
+      );
+      expect(capturedUIState.historyRemountKey).toBe(remountKeyBefore);
+
+      vi.useRealTimers();
+      (measureElement as Mock).mockReturnValue(undefined);
+    });
+
     it('handleClearScreen avoids a second clearTerminal write', () => {
       const clearSpy = vi.spyOn(console, 'clear').mockImplementation(() => {});
 

packages/cli/src/ui/AppContainer.tsx

@@ -119,7 +119,6 @@ const MCP_BATCH_FLUSH_MS = 16;
 const STARTUP_PROFILE_FINALIZE_CAP_MS = 35_000;
 import { useHistory } from './hooks/useHistoryManager.js';
 import { useMemoryMonitor } from './hooks/useMemoryMonitor.js';
-import { useResizeSettleRepaint } from './hooks/useResizeSettleRepaint.js';
 import { useWakeRepaint } from './hooks/use-wake-repaint.js';
 import { useThemeCommand } from './hooks/useThemeCommand.js';
 import { useFeedbackDialog } from './hooks/useFeedbackDialog.js';
@@ -3245,8 +3244,12 @@ export const AppContainer = (props: AppContainerProps) => {
     }
   }, [terminalWidth, availableTerminalHeight, activePtyId]);
 
-  // Repaint static history on the trailing edge of a resize burst (#4891).
-  useResizeSettleRepaint(terminalWidth, refreshStatic);
+  // Resize no longer repaints static history (#8004). The old settle →
+  // refreshStatic path wrote clearTerminal (destroying scrollback) and remounted
+  // <Static>, re-emitting all history in 50-item chunks — a scroll storm when
+  // the terminal's resize animation exceeded the debounce window (e.g. Ghostty
+  // panel toggle). Ink's dynamic region already re-renders on width changes via
+  // useTerminalSize; modern terminals reflow scrollback natively.
 
   // Repaint after the process resumes from OS sleep / suspend (lid close,
   // display sleep, Ctrl+Z → fg).  The terminal's screen buffer is stale but