Shutdown not unmounting drive cleanly

[Patrick Wiseman]

Hello:

I've been using the session manager's shutdown function without problems 
for a while, but the last two times, on rebooting I'm told that my drive 
was not shut down cleanly and fsck is invoked.  I shut down my last 
session manually and rebooted cleanly, so it seems that 
xfsm-shutdown-helper is what's causing the problem.  Any thoughts? 
(Debian testing, xfce 4.2).

Patrick