In https://bugs.launchpad.net/ubuntu/+source/unity/+bug/769650/comments/8, it is mentioned this can be due to bug 555641.
I limited the external monitor resolution to 800x600 in gnome-display-properties, there is no corruption.
In https:/ /bugs.launchpad .net/ubuntu/ +source/ unity/+ bug/769650/ comments/ 8, it is mentioned this can be due to bug 555641.
I limited the external monitor resolution to 800x600 in gnome-display- properties, there is no corruption.