[combobox][autocomplete] Fix popup closing on iOS VoiceOver

[atomiks]

• I have followed (at least) the PR section of the contributing guide.

This change was added as part of #3654, but it's not necessary following the changes in FloatingFocusManager in later commits of the PR.

This fixes the popup closing (input outside popup pattern) when swiping onto an option

[pkg-pr-new]

• base-ui-tanstack-start

• vite-css-base-ui-example

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/react@3859
  

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/utils@3859
  

commit: 15c91b3

[mui-bot]

Bundle size report

Bundle	Parsed size	Gzip size
@base-ui/react	▼-21B(-0.01%)	▼-1B(0.00%)

Details of bundle changes

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[greptile-apps]

Greptile Overview

Greptile Summary

Removes an unnecessary complexity introduced in PR #3654 by reverting to a simpler modal={!inputInsidePopup} logic instead of the conditional modal={inputInsidePopup ? modal : false}.

• Removes unused modal selector from store (line 50)
• Simplifies FloatingFocusManager modal prop to !inputInsidePopup (line 117)
• The change is a cleanup that became possible after FloatingFocusManager improvements in the same PR [menu][popover][combobox] Fix focus guard handling #3654
• Fixes iOS VoiceOver issue where popup would incorrectly close when swiping onto an option

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The change removes unused code and simplifies logic following improvements made to FloatingFocusManager in the same PR [menu][popover][combobox] Fix focus guard handling #3654. It's a straightforward cleanup that removes a selector that's no longer needed and simplifies the modal prop from a conditional expression to a simple negation. The change fixes a real iOS VoiceOver accessibility issue.
• No files require special attention

Important Files Changed

Filename	Overview
packages/react/src/combobox/popup/ComboboxPopup.tsx	Removed unused modal selector and simplified modal prop logic from conditional to !inputInsidePopup

[LukasTy]

This seems to regress the Popover closing when navigating forward with Tab on Firefox.
Like on the previous PR, with this change it closes Popovers only when doing backwards navigation (Shift + Tab).
Is it possible to fix both? 🤔

Besides, given that this has regressed, do you think it's possible to write a test cover this behavior?

[atomiks]

This seems to regress the Popover closing when navigating forward with Tab on Firefox.

That's not really possible because it's not touching anything to do with Popover. I tested and it's sometimes broken but is flaky. After refreshing several times it doesn't happen anymore.

I think that's the flake issue with React's hydration useId() error I mentioned in that PR, which breaks the focus guards. Because the race condition affects a bunch of other React behaviors -- React has released a fix for it in latest canaries.

You can confirm by looking in the console on the popup-tabbing experiment on localhost:

The focus guards are only broken when that error appears in the console, but you can't see it in the deploy preview.

Besides, given that this has regressed, do you think it's possible to write a test cover this behavior?

It's pretty tightly related to real screen reader operation with how it skips over aria-hidden and applies focus and isn't really testable with automation. We need to make sure changes to focus guards manually test iOS VoiceOver each time

[LukasTy]

Thanks for checking.
Indeed, I can confirm that if the console doesn't log the error, navigation works as expected on Firefox as well. 👌

As for the test - if we can't think of a way to test it outside of iOS, then I don't any more nitpicks.
Great work.