Fix infinite loop in ContextualMenu

[chiuam]

Platforms Impacted

• iOS
• macOS
• win32 (Office)
• windows
• android

Description of changes

This PR fixes a hang on tabbing inside a contextual menu. The hang happens in this while loop: while([nextViewToFocus isDescendantOf:focusZoneAncestor]) in FocusZone where it tries to get to the next key view that's outside of the current FocusZone view. In the context of ContextualMenu, the while loop tries to search for the next valid key view (outside the menu view) but it becomes infinite due to the fact that isDescendantOf: self returns true. The expected outcome for tabbing inside a contextual menu should be no op. Let's catch this edge case for the tab and shift-tab scenarios.

Verification

Before:

before.mov

After:

after.mov

1. Keyboard navigation works as usual in ContextualMenu
2. Ensured the behavior remains unchanged in the FocusZone test page

Pull request checklist

This PR has considered (when applicable):

• Automated Tests
• Documentation and examples
• Keyboard Accessibility
• Voiceover
• Internationalization and Right-to-left Layouts

[Harrie Shin (harrieshin)]

Isnt it still valid in some cases the tab should infact take u outside of focuszone?

[Harrie Shin (harrieshin)]

I think tab should work outside focuszone

[chiuam]

Isnt it still valid in some cases the tab should infact take u outside of focuszone?

Yes, I made sure tabbing through FocusZones still works as expected for all test cases in the test page. (tabbing into/out of disabled FZ is buggy but not a regression from this change)

[chiuam]

I think tab should work outside focuszone

It does work?

[Saad Najmi (Saadnajmi)]

Talked offline, approval with 2 comments:

1. Let's document with comments while([nextViewToFocus isDescendantOf:focusZoneAncestor]) means "there are no views left in the key view loop

2. Let's not introduce a new noOp boolean, and just leave the check as "nextViewToFocus === nil` with the same comment / logic

[Harrie Shin (harrieshin)]

before and after video please

[Harrie Shin (harrieshin)]

update the rest of the pr description as well please?

[chiuam]

update the rest of the pr description as well please?

I'll be updating the PR description with before and after videos. Anything else?

[Harrie Shin (harrieshin)]

might be worth testing arrow key as well after tab?

[chiuam]

hmm from the video of after, it didn't seem like focus changed based on your tab key? your mouse hover changed the context menu item selection?

Tab shouldn't move focus, so that's expected?

[chiuam]

might be worth testing arrow key as well after tab?

Untitled.mov

Up/down works after tab :)