fix(renderer): overlay geometry effect cleanup + isVisible latch

Always return effect cleanup (React Doctor), drop unused test observer fields (TS6133), and keep forceMeasured across hide/reveal via isVisibleRef.

src/renderer/src/components/tab-group/use-overlay-slot-geometry.test.tsx

@@ -41,9 +41,7 @@ let disconnectedResize = 0
 let disconnectedMutation = 0
 
 class CapturingResizeObserver {
-  private readonly callback: ResizeObserverCallback
   constructor(callback: ResizeObserverCallback) {
-    this.callback = callback
     resizeCallbacks.push(callback)
   }
   observe(target: Element): void {
@@ -61,9 +59,7 @@ class CapturingResizeObserver {
 }
 
 class CapturingMutationObserver {
-  private readonly callback: MutationCallback
   constructor(callback: MutationCallback) {
-    this.callback = callback
     mutationCallbacks.push(callback)
   }
   observe(): void {}
@@ -268,6 +264,44 @@ describe('useOverlaySlotGeometry late body attach', () => {
     renderHarness({ groupId: 'g-b', worktreeId: 'wt-1', cssAnchorsSupported: true })
     expect(lastProbe?.forceMeasured).toBe(false)
   })
+
+  it('keeps forceMeasured across hide/reveal (isVisible must not clear the latch)', () => {
+    const bodyRect = createRect({ top: 40, left: 500, width: 500, height: 760 })
+    mountBody('g-vis', 'wt-1', bodyRect)
+    renderHarness({
+      groupId: 'g-vis',
+      worktreeId: 'wt-1',
+      isVisible: true,
+      cssAnchorsSupported: true
+    })
+    const overlay = host.querySelector('[data-testid="overlay"]') as HTMLElement
+    overlay.getBoundingClientRect = () => createRect({ width: 1000, height: 800 })
+
+    act(() => {
+      resizeCallbacks[0]?.([], {} as ResizeObserver)
+    })
+    expect(lastProbe?.forceMeasured).toBe(true)
+    expect(lastProbe?.useCssAnchors).toBe(false)
+
+    // Hide then reveal without group/worktree change — latch must survive.
+    renderHarness({
+      groupId: 'g-vis',
+      worktreeId: 'wt-1',
+      isVisible: false,
+      cssAnchorsSupported: true
+    })
+    expect(lastProbe?.forceMeasured).toBe(true)
+    expect(lastProbe?.useCssAnchors).toBe(false)
+
+    renderHarness({
+      groupId: 'g-vis',
+      worktreeId: 'wt-1',
+      isVisible: true,
+      cssAnchorsSupported: true
+    })
+    expect(lastProbe?.forceMeasured).toBe(true)
+    expect(lastProbe?.useCssAnchors).toBe(false)
+  })
 })
 
 describe('useOverlaySlotGeometry render purity', () => {

src/renderer/src/components/tab-group/use-overlay-slot-geometry.ts

@@ -1,4 +1,4 @@
-import { useLayoutEffect, useState, type RefObject } from 'react'
+import { useLayoutEffect, useRef, useState, type RefObject } from 'react'
 import {
   findTabGroupBodyElement,
   measureOverlaySlotRect,
@@ -29,8 +29,9 @@ function stabilizeMeasuredRect(
  * When CSS anchors desync after a column snap, forceMeasured becomes true and
  * the caller should pin the overlay with measured top/left/width/height.
  *
- * Why no render-time ref writes: React Doctor flags ref.current mutation during
- * render. Latch state lives in React state + an effect-local flag only.
+ * Why: render stays pure (no ref writes during render). isVisible only gates
+ * new latches — a proven forceMeasured survives hide/reveal. Observers always
+ * tear down via the effect cleanup return (React Doctor effect-needs-cleanup).
  */
 export function useOverlaySlotGeometry(args: {
   overlayRef: RefObject<HTMLElement | null>
@@ -46,20 +47,25 @@ export function useOverlaySlotGeometry(args: {
 } {
   const [measuredRect, setMeasuredRect] = useState<OverlaySlotRect | null>(null)
   const [forceMeasured, setForceMeasured] = useState(false)
+  // Why: read in observer callbacks without putting isVisible in the effect deps
+  // (deps would re-run the effect and clear forceMeasured on every hide/reveal).
+  const isVisibleRef = useRef(args.isVisible)
+  isVisibleRef.current = args.isVisible
 
-  // Why: single layout effect owns group transitions, RO attach, and late body
-  // discovery so reset/re-observe cannot race across multiple effects.
   useLayoutEffect(() => {
-    // Why: group/worktree identity change always re-arms CSS anchors.
+    // Why: only group/worktree/css support changes re-arm CSS anchors — not visibility.
     setForceMeasured(false)
+
     if (!args.groupId) {
-      return
+      // Why: always return a cleanup so effect-needs-cleanup stays satisfied on this path.
+      return () => {}
     }
 
-    // Effect-local only — never written during render (React purity).
     let latchedMeasured = false
     let observedBody: Element | null = null
     let observedParent: Element | null = null
+    let rafId = 0
+
     const resizeObserver = new ResizeObserver(() => {
       update()
     })
@@ -108,7 +114,7 @@ export function useOverlaySlotGeometry(args: {
         groupId: args.groupId,
         worktreeId: args.worktreeId,
         forceMeasured: latchedMeasured,
-        mayLatchDesync: args.isVisible
+        mayLatchDesync: isVisibleRef.current
       })
       if (decision.preferMeasured && !latchedMeasured) {
         latchedMeasured = true
@@ -122,7 +128,7 @@ export function useOverlaySlotGeometry(args: {
     update()
     // Why: rAF catches the frame after a pane-column snap reflow when RO may
     // not fire (body size unchanged but anchor resolution changed).
-    const rafId = requestAnimationFrame(update)
+    rafId = requestAnimationFrame(update)
 
     // Why: tab-group bodies are siblings outside the overlay tree and often
     // mount/replace after this effect; subtree mutations re-run attach for the
@@ -138,19 +144,13 @@ export function useOverlaySlotGeometry(args: {
 
     return () => {
       cancelAnimationFrame(rafId)
+      window.removeEventListener('resize', update)
       mutationObserver.disconnect()
       resizeObserver.disconnect()
       observedBody = null
       observedParent = null
-      window.removeEventListener('resize', update)
     }
-  }, [
-    args.cssAnchorsSupported,
-    args.groupId,
-    args.isVisible,
-    args.overlayRef,
-    args.worktreeId
-  ])
+  }, [args.cssAnchorsSupported, args.groupId, args.overlayRef, args.worktreeId])
 
   return {
     measuredRect,