Note this is XFCE not Gnome classic. I have also seen the bug happen in Unity, but it was a long time ago and I have no idea if it still happens there.
** Attachment added: "screenshot of the bug" https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1067951/+attachment/3463884/+files/firefox.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1067951 Title: Firefox randomly loses window decoration in Gnome Classic (Compiz) To manage notifications about this bug go to: https://bugs.launchpad.net/compiz/+bug/1067951/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs