fix: target current browser page for grab mode

src/renderer/src/components/browser-pane/useGrabMode.test.ts

@@ -0,0 +1,87 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+
+function createReactHookHarness() {
+  const refs: { current: unknown }[] = []
+  const states: unknown[] = []
+  const effects: { effect: () => void | (() => void); deps: readonly unknown[] | undefined }[] = []
+  let refIndex = 0
+  let stateIndex = 0
+
+  return {
+    beginRender: () => {
+      refIndex = 0
+      stateIndex = 0
+      effects.length = 0
+    },
+    effects,
+    react: {
+      useCallback: <T extends (...args: never[]) => unknown>(callback: T): T => callback,
+      useEffect: (effect: () => void | (() => void), deps?: readonly unknown[]) => {
+        effects.push({ effect, deps })
+      },
+      useRef: <T>(initialValue: T): { current: T } => {
+        const index = refIndex
+        refIndex += 1
+        refs[index] ??= { current: initialValue }
+        return refs[index] as { current: T }
+      },
+      useState: <T>(initialValue: T): [T, (value: T) => void] => {
+        const index = stateIndex
+        stateIndex += 1
+        states[index] ??= initialValue
+        return [
+          states[index] as T,
+          (value: T) => {
+            states[index] = value
+          }
+        ]
+      }
+    }
+  }
+}
+
+describe('useGrabMode', () => {
+  afterEach(() => {
+    vi.doUnmock('react')
+    vi.doUnmock('@/hooks/useMountedRef')
+    vi.resetModules()
+    vi.unstubAllGlobals()
+  })
+
+  it('uses the latest browser page when toggled before the page-change effect runs', async () => {
+    const harness = createReactHookHarness()
+    const setGrabMode = vi.fn(async () => ({ ok: true }))
+    vi.doMock('react', () => harness.react)
+    vi.doMock('@/hooks/useMountedRef', () => ({
+      useMountedRef: () => ({ current: true })
+    }))
+    vi.stubGlobal('window', {
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+      api: {
+        browser: {
+          setGrabMode,
+          awaitGrabSelection: vi.fn(() => new Promise(() => {})),
+          cancelGrab: vi.fn()
+        }
+      }
+    })
+    const { useGrabMode } = await import('./useGrabMode')
+    const render = (browserPageId: string) => {
+      harness.beginRender()
+      // oxlint-disable-next-line react-hooks/rules-of-hooks -- test harness mocks React's hook dispatcher directly.
+      return useGrabMode(browserPageId)
+    }
+
+    render('page-1')
+    harness.effects[0]?.effect()
+    const grab = render('page-2')
+    grab.toggle()
+    await Promise.resolve()
+
+    expect(setGrabMode).toHaveBeenCalledWith({
+      browserPageId: 'page-2',
+      enabled: true
+    })
+  })
+})

src/renderer/src/components/browser-pane/useGrabMode.ts

@@ -46,6 +46,9 @@ export function useGrabMode(browserPageId: string): GrabModeHook {
   const activeOpIdRef = useRef<string | null>(null)
   const grabTabIdRef = useRef<string | null>(null)
   const browserTabIdRef = useRef(browserPageId)
+  // Why: toolbar/key handlers from the latest render can fire before passive
+  // effects run after a page switch, so keep the target page current in render.
+  browserTabIdRef.current = browserPageId
   const mountedRef = useMountedRef()
 
   // Why: when the browser page changes while grab is active, cancel the