Oh man, another clueless one... Dude, throw alway your colorfull googles and see the ENTIRE problem, please? Just one example: I start KDE, okay. More or less a "expected" desktop Windows-like. Now, open Kate to do some file editing. Ok, works as expected. Now open something GNOME-based. oh oh, copy/paste broken (because the application in question do not like to accept the default KDE way to do this). Try pgAdmin3, or some application using wxWidgets. Oh oh... WTF is going on? Another one have a GUI, but you need the CLI to be able to make then work.
Short version: IF, and i can't stress enought this IF, you use a more or less sane desktop like KDE, many applications still like to do things in bizarre and obscure ways. And worse, many of them do not like to play nice with the others.