I can confirm this on Kubuntu breezy. To solve this, one has to edit /usr/share/applications/kcmgtk-xdg.desktop and replace "Exec=kcmshell kcmgtk" on line 4 by "Exec=kcmshell kcmgtk-xdg" -- incorrect exec command in kcmgtk-xdg.desktop file https://launchpad.net/malone/bugs/24209