Extension icons and flexible spaces disappear when toggling full-screen on videos

[markx86]

Describe the bug
Sometimes, when toggling full-screen on a video, the right most extension icon or flexible space disappears.

To Reproduce
Steps to reproduce the behavior:

1. Open any video player that allows full-screen.
2. Enter and then exit full-screen.
3. The right most extension icon (or flexible space) should have disappeared.

Expected behavior
The right most extension icon/flexible space remains where it is.

Setup information

• OS: Fedora 37
• Installation method: flatpak
• Firefox version: 109.0
• Theme version: from master branch

Additional context
Entering the "customize toolbar" page restores the missing elements.
This problem was already happening in version 108, but I couldn't track it down. Thought I've seen some similar issues about this, like #540 and #492. I still don't quite understand what causes it, as sometimes toggling full-screen works just fine and no elements from the toolbars disappear.

[markx86]

Reinstalling Firefox seems to have fixed the issue. I think I wasn't updating the theme properly, and I was still stuck on an older version...

[mattblaha]

I still see this happen pretty often even after resetting firefox and updating the plugin to latest. Also on Fedora 37, 109, flatpak.

[markx86]

Yeah, this has happened to me again, but it seems like it's even more random than before. I thought it was just me at this point. It's probably good to reopen this issue.

[mattblaha]

Yeah it's not just you. I've considered filing a bug a few times, but like you, can't figure out a pattern and figured out I eventually would and then would file a decent bug.

It's been a thing since 108 at least, I've tried switching from the flatpak to the native package, resetting both and reinstalling the theme, it still seems to happen unpredictably.

[mattblaha]

I've updated to include this commit -- will post if I see the issue again.

Thanks!

[mattblaha]

Still happens unfortunately, I'm not sure exactly when, but my window I'm running in right now lost the flex spaces.