FocusScope skips a Tab stop after an exiting sibling scope unmounts

Start with the FocusScope cleanup condition and the other call sites of isAncestorScope; then run the forward- and reverse-Tab regression tests mentioned in the issue. Done means preserving an active descendant when an ancestor unmounts, with both regression tests passing and the existing whole-subtree focus restoration test unchanged.

🐛 Bug Report

When one overlay opens another before it finishes closing, unmounting the first overlay can break keyboard navigation in the second. One Tab skips a focusable element. On a fresh opening, Shift+Tab can move focus outside the second overlay even though its FocusScope has contain enabled.

The two scopes are siblings under an outer FocusScope in the React component tree. The second scope stays mounted, and focus is already inside it when the first scope unmounts.

🤔 Expected Behavior?

Removing the closing overlay should not change keyboard navigation in the overlay that remains open. Tab should move to the next focusable element, and Shift+Tab from the first element should wrap to the last. Focus should stay within the containing scope.

😯 Current Behavior

After the closing overlay unmounts, the first Tab skips the next button. Testing Shift+Tab instead on a fresh opening moves focus to a button outside the remaining overlay.

💁 Possible Solution

Change FocusScope cleanup so that it resets activeScope only when the scope being removed is itself active. If the active scope is a descendant that remains mounted, preserve it while removing its ancestor and reparenting it.

In the cleanup condition, this means replacing scopeRef === activeScope || isAncestorScope(scopeRef, activeScope) with scopeRef === activeScope. The isAncestorScope helper remains in its other call sites.

The added forward and reverse Tab regression tests fail without this change and pass with it. The existing whole-subtree focus restoration test also passes unchanged.

🔦 Context

Selecting a menu item opens another popover. The menu briefly remains mounted while the new popover opens. Once the menu unmounts, the first Tab in the new popover skips a button.

🖥️ Steps to Reproduce

https://codesandbox.io/p/sandbox/xfgnvy

1. Open the standalone preview.
2. Focus Open menu and press Space. Wait for focus to reach Choose date and time.
3. Press Space again, then wait for the first overlay to fade out. Focus is now on September, the first enabled button in the second overlay.
4. Press Tab once. Expected: 2026. Actual: Next month, skipping 2026.
5. Reload and repeat steps 2–3. Press Shift+Tab instead. Expected: Next month (wrap to the last button). Actual: Open menu, outside the second overlay.

After the closing overlay unmounts, a single Tab skips a button in the overlay that remains open, even though its FocusScope still has contain enabled.

Version

react-aria@3.52.1

What browsers are you seeing the problem on?

Chrome

If other, please specify.

No response

What operating system are you using?

macOS 26.4.1, arm64

🧢 Your Company/Team

No response

🕷 Tracking Issue

N/A