So I installed Ubuntu with Unity 14.04 and then decided I wanted to try Xfce, so I used apt-get to install it, and after logging in the Xfce enviroment I noticed that if I return to unity and logoff or suspend, my login screen(aka the one where you select which window manager you want to use and type your username and password) changes from the default Unity one to the Xfce one, is there a way to lock one or the other?
I added this:
[SeatDefaults]
greeter-session=unity-greeter
to /etc/lightdm/lightdm.conf
And it seemed to have fixed my issue.