Comment 93 for bug 1181666

I can say with reasonable confidence that this bug is introduced by gnome-shell-extension-ubuntu-dock_64ubuntu7_all.deb. I downgraded by downloading gnome-shell-extension-ubuntu-dock_64ubuntu6_all.deb from https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/3701.1-deletedppa/+build/16616785 and installing with dpkg. No dependency issues or conflicts were identified and the package installed without issue. I restarted my test system and the problem appears fixed.

I'll report back if this is a red herring, but I thought I should report as soon as possible so that other's might benefit.