I see that you're running firefox version 91.0. This version is outdated, I strongly suggest you update to the latest version (97.0) and check whether the problem is fixed there.
The problem sounds similar to this upstream bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1719988. ** Bug watch added: Mozilla Bugzilla #1719988 https://bugzilla.mozilla.org/show_bug.cgi?id=1719988 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1955827 Title: Firefox without 'TitleBar' alters the look of MATE buttons To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-mate/+bug/1955827/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
