Recently I ran into the problem that after resuming from standby and changing my display configuration my desktop seemed to be no longer displayed.
After a bit of searching, I found out that the KDE desktop was still running but my Gnome desktop installed in parallel was started and was covering it. For this reason, I saw an empty desktop. The problem is that somehow nautilus is started when using a KDE session. Nautilus is not only a file manager but also starts the desktop component which then can interfere with KDE’s desktop.
In order to prevent nautilus from starting the desktop component, you can use gconf-editor to reconfigure nautilus. Start gconf-editor and navigate to apps/nautilus/preferences in its folder structure and uncheck “show desktop”. After that the desktop will not be automatically started when nautilus is started.
As I am only using nautilus within KDE and not Gnome as a window manager this is of no problem for me. If you also use Gnome in a session you probably have to check if your Gnome session still behaves correctly with the same user.