Cant select with what window manager want to start X.
I think its for unity-greeter.
The icon that appears next to your username and let you start X with unity-2d, gnome, unity, kde, etc have gone and I cant switch.
I DONT want to change my default window manager, only switch it on the lightdm screen. It has disappeared in Ubuntu 12.10 I think.
Anyone?
sudo dpkg-reconfigure gdm
command to switch window manager