I have the same problem, not only for Update Manager, but also for : Gnote, PDF Mod, Gwibber, Hotot...
Described here : https://bugs.launchpad.net/ubuntu/+source/unity/+bug/959093
I have the same problem, not only for Update Manager, but also for : Gnote, PDF Mod, Gwibber, Hotot...
Described here : https:/ /bugs.launchpad .net/ubuntu/ +source/ unity/+ bug/959093