Problem came back. Reinstalling compiz was not what made it dessapear... But I also replaced Firefox with Abrowser...
So after browsing the web, I think I have found the workaround: I deleted / recreated my .mozilla/firefox settings. THIS makes the problem disappear for me. See also http://ubuntuforums.org/showthread.php?t=833714 -- Firefox problems with desktop-effects https://bugs.launchpad.net/bugs/99740 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs