I experience this problem on Ubuntu (https://bugs.launchpad.net/ubuntu/+source/cinnamon/+bug/1248414), and I noticed a message that cinnamon issues some time after this happens, I think it might be related (or might not):
Window manager warning: CurrentTime used to choose focus window; focus window may not be correct. Just in case it may help... Eugene -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
