Upper bookmarks are no more reachable in FF 145

### Guidelines

- [x] I have read [how to report a new issue](https://github.com/Aris-t2/CustomCSSforFx/issues/4)
- [x] I have used the [latest release](https://github.com/Aris-t2/CustomCSSforFx/releases/latest)
- [x] I have set the `toolkit.legacyUserProfileCustomizations.stylesheets` in `about:config` to `true`

### Does the issue occur without any files inside /chrome/ folder?

No

### Description of the Issue

- Click on folder with many items in bookmark bar.
-> the column of items is automatically scrolled to the bottom part.
- Use mouse wheel to scroll to the upper entries and move mouse to the wanted entry.
-> the column is again automatically scrolled to the bottom part, so the wanted bookmark item is not reachable.

### Issue description, userChrome.css/userContent.css 'settings' the issue occurs with and steps to reproduce the issue

[userChrome.css](https://github.com/user-attachments/files/23827503/userChrome.css)

### Does the issue occur with the most recent version of CustomCSSforFx (release/test/dev build)?

Yes, with the latest release: 4.7.5

### Screenshots showing the issue

### System information

- OS & OS version: Ubuntu 24.04
- DPI/HiDPI/scaling value, if not 100% (e.g. 125%, 150%...): No
- Firefox version: 145.0.1
- Firefox theme (e.g. default, build in light/dark, external theme + link): default

Start by reproducing the bookmark-folder behavior in Firefox 145.0.1 with the attached userChrome.css, then inspect which custom rules affect the bookmark menu's scrolling. Done means the upper bookmark entries remain reachable after scrolling and moving the pointer over the menu.

Written by the indexing model from the issue text.