Bookmarks toolbar is empty after fullscreen from videoplayer.

### Describe the bug

Bookmarks toolbar becomes like this after open video play in fullscreen and exit from it.
If I open "Customise toolbar", don't change anything and click "done" bookmarks will appear again.

### Expected behavior

Was okay on firefox 128ESR, bookmarks didn't disappear after fullscreen.
It also okay if I delete UIfix.
And it also okay with F11 fullscreen.

### Screenshots

before fullscreen:

After fullscreen:

### OS

Windows 10

### OS - Others

_No response_

### Firefox Version

140.4.0esr x64

### Distribution

- [ ] [Original Lepton](https://github.com/black7375/Firefox-UI-Fix)
- [x] [Lepton's photon style](https://github.com/black7375/Firefox-UI-Fix/tree/photon-style)
- [ ] [Lepton's proton style](https://github.com/black7375/Firefox-UI-Fix/tree/proton-style)

### Theme

- [ ] Light
- [x] Dark
- [ ] Alpenglow (System: Light)
- [ ] Alpenglow (System: Dark)
- [ ] System Default
- [ ] Others: (e.g. [Photon Colors](https://addons.mozilla.org/en-US/firefox/addon/photon-colors/), [Google Chrome Dark](https://addons.mozilla.org/en-US/firefox/addon/google-chrome-dark/), [Fairytale Of Nature](https://addons.mozilla.org/en-US/firefox/addon/fairytale-of-nature/))

### Theme - More Info

_No response_

### `user.js` setup

I didn't change default user.js from latest release.

### Additional context

_No response_

Reproduce on Windows 10 with Firefox 140.4.0esr using Lepton's photon style, then compare video fullscreen with F11 fullscreen and with UIfix removed. No source file or test is named; done means the bookmarks toolbar remains visible after entering and exiting video fullscreen without using Customize toolbar.

Written by the indexing model from the issue text.