Comment 7 for bug 1312184

I resolved the issue by installing all *mir* packages -- I noticed in ps -A that Xorg was run with some mir option. After uninstalling all libraries related to mir, everything works smoothly again. (Keyboard lag was also resolved by that, which is not a part of this bugreport).

This report should be kept open (perhaps re-assigned to mir) until it is resolved properly, though.