Comment 19 for bug 1462841

I got the bug after just turning off and on window spread.

I managed to fix the bug by reinstalling xorg-server with this tutorial:
https://www.computersnyou.com/4945/re-install-xorg-xserver-completely-ubuntu/

After reinstalling the xorg server, ubuntu desktop, unity tweak tools and a reboot; click on "Restore Defaults" on the "Window Spread" tab on unity tweak tool.