Starting xffm causes my desktop background to change to black. It adds icons to the desktop....computer, home, and run. It removes the ability to right click on the desktop. The only way around this that I know of is to do a full uninstall on xfce, then manually delete parts of xfce not uninstalled by the full uninstall, then reinstall xfce.
I've got the same problem since the last upgrade (using debian testing packages) the only workaround I found is to use kdedesktop instead of xfcedesktop :(
Yeah, this is not a bug: you can avoid xffm taking over the desktop by specifying --no-desktop in the command line. This behaviour is going to change since it the same ugly behaviour of nautilus filemanager.