Comment 47 for bug 1181666

I sometimes find that not only mouse clicks get blocked, but everything except ubuntu-dock and the Activities overview stops accepting input. (I can't ALT-F2 to restart gnome, and I can't ALT-tab between apps.) On a couple of occasions I found that it was a single app that had captured input (and crashed), and quitting the rogue app via ubuntu-dock or the Activities overview fixed the issue. But this isn't always possible because some applications put up a dialog asking if you want to quit, and since you can't click on the dialog box, you can't quit them.

Is the bug I'm describing related to this one, or something different?

FWIW, I did find that "killall -3 gnome-shell" will restart the shell without closing your applications if you can manage to get to a tty console. Is there a way to restart the shell from the Activities overview? That would be a good workaround for this bug.