Comment 2 for bug 1217877

Is this still hapenning with latest version of unity-system-compositor and Mir?

If so, can you try if lp:~afrantzis/mir/lp-1217877-possible-fix makes a difference?

I have created a package you can try for convenience:
$ wget http://people.ubuntu.com/~afrantzis/libmirplatform_0.0.10+13.10.20130904-0ubuntu2_amd64.deb
$ sudo dpkg -i libmirplatform_0.0.10+13.10.20130904-0ubuntu2_amd64.deb

To go back to the original version do:

$ sudo apt-get install libmirplatform=0.0.10+13.10.20130904-0ubuntu1

Ensure you set up lightdm to use Mir, and restart lightdm (see http://unity.ubuntu.com/mir/using_mir_on_pc.html)