blank panel

[Gavin Chester]

I have a small (4 terminal) terminal server setup with all thin-client
users running Xfce4.

One of the users "claimed" they simply changed their wallpaper, but in
the process their panel is present only as a grey bar devoid of any
icons or other features - not even the end bars.  We don't have the
session manager running so they don't get the option to save their
settings on logging off.  Items like wallpaper changes are saved, but
not the apps that are open, so that says to me that the session is not
being saved. 

I've killed X on their session (ctl+alt+bckspc) and got them to log in
again, and I've killed the panel as a process when running under their
name (as root), and I've even rebooted their terminal.  BTW: that shows
that the panel _is_ running when they are logged in.  In no case does
the panel seem to come back as anything resembling "a panel" _except_ I
saw the date/time plugin come back after the first restart, only.  Any
clues welcome :-/    

Gavin