Default desktop environment not being saved.

[Akegata]

I upgraded to 11.10 a couple of hours ago, and installed gnome classic and gnome-shell. Everything works fine, except the prefered desktop environment isn't saved.
If I restart the machine, I'm always kicked into Unity if I have autologin enabled, even though I log out manually and choose Gnome. Shouldn't the latest manually chosen environment be the one you get?
Can this be specified in a config file or something?

[Akegata]

For anyone else having this problem (that seems to be a bug in lightdm), here's the solution: http://ubuntuguide.net/ubuntu-11-10-how-to-auto-login-gnome-shell-gnome3-desktop