Testing lightdm not remembering session

[David Christensen <dpchrist@holgerdanske.com>]

debian-user:

I installed Debian Testing amd64 with the Debian desktop environment.  I 
then installed task-xfce-desktop, including lightdm and setting lightdm 
as the default desktop manager.


When I login to an xfce desktop, lightdm is running and gdm is not:

2012-07-31 17:01:54 root@i72600s ~
# ps -A | grep lightdm
 2364 ?        00:00:00 lightdm
 6530 ?        00:00:00 lightdm

2012-07-31 17:01:58 root@i72600s ~
# ps -A | grep gdm


When I log out, leaving the check box "Save session for future login" 
checked", and then login again leaving the "Default Xsession" drop-down 
alone, I am logged in to a Gnome desktop, in spite of the contents of 
~/.dmrc:

2012-07-31 17:04:01 dpchrist@i72600s ~
$ cat .dmrc

[Desktop]
Session=xfce


Any suggestions?


TIA,

David