[WP 6.9] Format Library: language popover opens twice in Firefox

[t-hamano]

Description

• Originally reported at Trac: https://core.trac.wordpress.org/ticket/64410
• Props to @oldrup who first reported it and @sabernhardt and @soyebsalar01 who tested it.

In Firefox, the popover for language formatting opens twice. This is a new issue in 6.9.

Note that this issue is not reproducible in the latest Gutenberg. If necessary, let's identify the commit that fixed this issue and backport it to the 6.9 branch.

Step-by-step reproduction instructions

1. Access https://playground.wordpress.net/?wp=6.9 in Firefox
2. Open a post and select any word
3. Click the "Language" button in the block toolbar
4. The language popover opens
5. Fill the Language field with en
6. Click the Apply button
7. The language popover opens again, with the language field empty

Screenshots, screen recording, code snippet

11d7c009b43e64eb1fb171f47fade5fe.mp4

Environment info

No response

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[t-hamano]

I've identified the PR that caused this issue and the PR that fixed it.

Status	Pull request	Gutenberg version	Is it included in WordPress 6.9?
Problem occoured	#71252	21.7	Yes
Problem solved	#72376	22.0	No

In other words, we should just backport #72376 to 6.9.

[t-hamano]

In other words, we should just backport #72376 to 6.9.

With this in mind, I would like to close this issue.

[Mamaduka]

Good find, @t-hamano!