Comment 2 for bug 778808

@Davide - On your example I opened the Main Menu editor (alacarte) and changed the command for Nautilus from:

nautilus %u .

to

nautilus %u .

This change immediately took affect in the launcher as well and solves the problem nicely. Nautilus can now be successfully launched when the file manager is handling the desktop. However, this still needs to be fixed so a work around by the user isn't needed I believe since this may not be the best way to do it.