Multiple X Sessions not working right

[Matt Morgan]

I know that to enable mutiple X sessions (e.g., one on Ctrl-Alt-F7,
one on Ctrl-Alt-F8) I'm supposed to edit /etc/X11/gdm/gdm.conf, to
uncomment a line that says

#1=Standard

and then restart X. This doesn't work perfectly for me. I did that,
and this is what I see:

1) when I hit Ctrl-Alt-F8, I just get a flashing cursor. No login
prompt (not even text).
2) If I login to the Ctrl-Alt-F7 console, it's fine. If I then hit
Ctrl-Alt-F7 again, without logging out first, I get another X login
screen. I can login as another user; or, if I login as the same user,
I get a little dialog that warns me that I'm already logged in, and
asks if I want to get back on my existing session, start a new
session, or abort.
3) Once I have two login sessions up, Ctrl-Alt-F7 doesn't do anything,
so it's impossible to switch users at that point without logging off
from the second session.

So it's like I'm getting the two X sessions I want, only they're on
the same virtual console instead of two different ones.

This is a Dell Latitude D500 running FC3. Thanks for any help!