I think the medium classification for this is too low. This can really impact your system. If you don't have a terminal window open and no shortcut to one on the desktop you are effectively locked up. Alt+F2 fails me in this situation, too.
I also had a complete system hang sometime after leaving gnome-panel in this state without killall -1 gnome-panel, which corrects the problem. -- Clicking on clock applet hangs gnome-panel https://bugs.launchpad.net/bugs/203527 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is a bug assignee. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs