Hi Rex (or anyone else that may know), I mentioned this in another thread, but it probably belongs here...
I've switched all but one of my machines from GDM to LightDM (via updates-testing). The one I haven't switched is an Atom based Mini-ITX machine that 'thinks' it has a laptop display in addition to the attached monitor. Although disabled within display preferences once Xfce is loaded, the login manager thinks it's there. In GDM, I get a blank screen (well, I get the fireworks wallpaper, but I can move my mouse cursor to the right until it's visible and hit enter, and the login box will re-apper. In LightDM, I can't figure out how to force it to my visible screen...
Any ideas on this? Wondering if it should be reported upstream.