Comment 10 for bug 1749481

This may or may not be worth mentioning but the reason I totally purged lightdm was just using dpkg to change to gdm3 returns an error:

lance@lance-conroe:~$ sudo dpkg-reconfigure gdm3
[sudo] password for lance:
gdm.service is not active, cannot reload.
invoke-rc.d: initscript gdm3, action "reload" failed.

Of course I could also have run sudo dpkg-reconfigure lightdm and accomplished the same thing.