fix: address Codex review on PR #3204

components/terminal/autocomplete/terminalAutocompleteLayout.ts

@@ -584,6 +584,18 @@ export function resolveAutocompletePopupAnchorInViewport(
   );
 }
 
+/** Whether the clamp bounds moved since the last reposition (layout-driven change). */
+export function didAutocompleteClampViewportChange(
+  prev: PopupClampViewport | null,
+  next: PopupClampViewport,
+): boolean {
+  if (!prev) return false;
+  return prev.left !== next.left
+    || prev.top !== next.top
+    || prev.width !== next.width
+    || prev.height !== next.height;
+}
+
 /**
  * Next stored popup viewport when the command-start / cursor anchor moves.
  * Returns `prev` when nothing changed so callers can skip a React update.

components/terminal/autocomplete/useTerminalAutocomplete.ts

@@ -31,11 +31,14 @@ import { isWindowsShellLineInput, shouldWriteAutocompleteLivePreview } from "./l
 import {
   areSubDirPanelsEqual,
   areSuggestionsEqual,
+  didAutocompleteClampViewportChange,
   nextAutocompletePopupAnchorViewport,
+  resolveAutocompleteClampViewport,
   resolveAutocompleteCursorCell,
   resolveAutocompleteCwdWithSource,
   resolveAutocompletePopupAnchorInViewport,
   resolvePreservedSuggestionIndex,
+  type PopupClampViewport,
 } from "./terminalAutocompleteLayout";
 import { handleTerminalAutocompleteInput } from "./terminalAutocompleteInput";
 import { handleTerminalAutocompleteKeyEvent } from "./terminalAutocompleteKeyEvent";
@@ -358,6 +361,13 @@ export function useTerminalAutocomplete(
   const previewBaselineRef = useRef<string>("");
   /** Whether a popup candidate is currently rendered into the command line (#1005). */
   const previewActiveRef = useRef(false);
+  /**
+   * Clamp viewport measured at the last reposition. The popup derives its
+   * clamp bounds at render time, so a layout-only resize (e.g. pixel shrink
+   * from opening a side panel) must force a re-render even when the anchor
+   * did not move (#3204).
+   */
+  const lastClampViewportRef = useRef<PopupClampViewport | null>(null);
   /** Monotonic counter to invalidate stale async sub-dir fetches */
   const subDirFetchVersionRef = useRef(0);
   /**
@@ -477,6 +487,7 @@ export function useTerminalAutocomplete(
     }
     echoValidationTypedRef.current = null;
     echoValidationStartedAtRef.current = null;
+    lastClampViewportRef.current = null;
     ghostAddonRef.current?.hide();
     completionAbortRef.current?.abort();
     completionAbortRef.current = null;
@@ -509,6 +520,16 @@ export function useTerminalAutocomplete(
     const term = termRef.current;
     if (!term) return;
 
+    // Track clamp bounds so a layout-driven resize (anchor unchanged) still
+    // forces a render — the popup recomputes resolveAutocompleteClampViewport
+    // only when it re-renders (#3204).
+    const clampViewport = resolveAutocompleteClampViewport(containerRef.current);
+    const clampChanged = didAutocompleteClampViewportChange(
+      lastClampViewportRef.current,
+      clampViewport,
+    );
+    lastClampViewportRef.current = clampViewport;
+
     setState((prev) => {
       if (!prev.popupVisible || prev.suggestions.length === 0) return prev;
       const { prompt } = getAlignedPrompt(term, typedInputBufferRef.current, typedBufferReliableRef.current);
@@ -542,7 +563,11 @@ export function useTerminalAutocomplete(
         prev.expandUpward,
         anchor,
       );
-      if (!nextAnchor) return prev;
+      if (!nextAnchor) {
+        // Anchor unchanged but the clamp viewport moved (container resized);
+        // re-render so the popup can re-clamp its width/position.
+        return clampChanged ? { ...prev } : prev;
+      }
 
       return {
         ...prev,

components/terminal/terminalAutocompleteLayout.test.ts

@@ -4,6 +4,7 @@ import assert from "node:assert/strict";
 import {
   clampAutocompletePopupGeometry,
   computeAutocompletePopupPlacement,
+  didAutocompleteClampViewportChange,
   nextAutocompletePopupAnchorViewport,
   resolveAutocompleteAnchorInViewport,
   resolveAutocompleteClampViewport,
@@ -874,3 +875,17 @@ test("nextAutocompletePopupAnchorViewport is a no-op when the stored viewport is
     null,
   );
 });
+
+test("didAutocompleteClampViewportChange detects layout-only viewport changes", () => {
+  const viewport = { left: 0, top: 0, width: 800, height: 600 };
+  assert.equal(didAutocompleteClampViewportChange(null, viewport), false);
+  assert.equal(didAutocompleteClampViewportChange(viewport, { ...viewport }), false);
+  assert.equal(
+    didAutocompleteClampViewportChange(viewport, { ...viewport, width: 700 }),
+    true,
+  );
+  assert.equal(
+    didAutocompleteClampViewportChange(viewport, { ...viewport, left: 12 }),
+    true,
+  );
+});