Middle mouse button no longer opens new tab

[riwarek]

Guidelines

• I have read how to report a new issue
• I have used the latest release
• 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

When I click on tab bar with middle button new tab doesn't appear.
My Firefox is 146.0.1.
CustomCSSfoFx is 4.7.5
When I use version 4.6.2 this bug doesn't exists.

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

Just click on the tab bar with middle mouse button.

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

Yes, with the latest release

Screenshots showing the issue

no screenshots needed

System information

• OS & OS version: Win 11
• DPI/HiDPI/scaling value, if not 100% (e.g. 125%, 150%...):
• Firefox version: 146.0.1
• Firefox theme (e.g. default, build in light/dark, external theme + link): Brushed Metal (Chrome) 2.0 (this is addon)