userChrome.css instruction to hide X on tab ignored when browser width is narrow

[ThermoMan]

What happened?

Bug is in Waterfaox 6.6.3
I compared to Firefox 142.0.1 and 143.0.1 (where it works "correctly" in both versions)

I use an Add On to place a close tab button on my toolbar and I use userChrome.css to remove the "X" on the tab.

Here is the Add On
https://addons.mozilla.org/en-US/firefox/addon/close-the-tab-button/

Here is the CSS

#tabbrowser-tabs .tabbrowser-tab .tab-close-button {
  display:none !important;
}

To reproducer the bug open a few tabs (maybe 8). If your browser is using most of the width of your screen then the CSS works correctly.

But now make the browser window narrower (it doesn't take too much) and as you mouse over tabs that are not the present tab, that "X" will appear.

This is important to me because I have trouble with precise mouse placement and often when trying to bring another window to the front I end up closing it instead.

Reproducible?

• I have checked that this issue cannot be reproduced on Mozilla Firefox.

Version

6.6.3

What platform are you seeing the problem on?

Windows

[poisongodmachineBR]

I would also like this to be solved

EDIT:
I've just solved it. Along with the userChrome.css file, also open up about:config, search for userChrome.tab.close_button_at_hover and change it to false. Restart Waterfox.

[MrAlex94]

You can do as suggested above, or just disable Waterfox's customisations in Settings > Look & Feel to use your own userChrome changes.