Comment 1 for bug 40072

I'm able to reproduce the bug in this way:
install kubuntu-desktop and login into a KDE session. After logging out, if you try to login into an XFCE session you get the wallpaper and nothing else. If you remove the file ".gtkrc-2.0" in the user home directory you can login again into XFCE, but the next time you will use KDE the file will be created again (it is located in the kubuntu-default-settings package). So, I don't know if the bug is to be assigned to xubuntu-desktop or kubuntu-desktop...