Screensaver under compiz logs the user out

[Alan McKinnon]

Hi,

I have a Dell Latitude D810 running an up to date Dapper. When running
plain metacity, gnome-screensaver works correctly. When using compiz, if
I'm away from the machine for more than 10 minutes I come back to find
the gdm login screen. I've never seen it happen, but the 10 minute
interval leads me to believe it's related to the screensaver. I would
rather the machine did not do this :-) Related settings:

Screensaver interval: 10 minutes
Activate screensaver when session is idle: checked
Lock screen when screensaver is active: checked

Power management stuff (running on AC settings):
Put display to sleep: 30 minutes
Put computer to sleep: never
When lid is closed: blank screen

My .Xsession:
alan at alanm:~$ cat .Xsession
#!/bin/sh
Xgl :1 -fullscreen -ac -accel xv -accel glx:pbuffer &
DISPLAY=:1
gnome-window-decorator &
compiz gconf decoration wobbly fade minimize cube rotate zoom scale move
resize place menu switcher &
exec gnome-session

I'll try various settings throughout the day and see what gives.
Meanwhile, does anyone have some pointers to ease the process?

alan