Can one stop the xfce session manager changing desktops when it finishes startup?

[Chris G]

I have a pretty standard xubuntu 10.04 system.  When I log in my
desktop appears and is quite usable while the various autostarted bits
and pieces get started up in the background.  However, after they have
all loaded, the xfce4 session manager insists on moving me to the
workspace I was on when I last saved my session.

This can be really annoying because it's usually several seconds after
I have logged in and started doing something that it happens, so if I
am using a workspace other than the one saved by the session manager I
suddenly get flipped to the wrong workspace.

Is there any way of preventing the session manager doing this? Or,
alternatively is there a way to get the session manager to do its
stuff first of all the autostarted processes?

-- 
Chris Green