Comment 5 for bug 1218309

This has been a problem for me for probably about a year. It often happens with vmware player open in my gnome-shell. I've become so used to it that I was actually looking for a keyboard shortcut to launch the killall gnome-shell! It happens to me two or three times a week so if someone tells me how, I can easily give you a dump of gnome-shell/X/etc when it happens. I've colleagues with the same problem.

For the record I'm using 12.04 and gnome-shell 3.4.1.