Keeping gnome-desktop installed without booting it auto

I like to use file-roller but I use KDE 4. To use it, I must install gnome-desktop. I realized that every time I boot, gnome-desktop boots with KDE which is kind of annoying. I can I stop it from booting automatically?

If you have auto-login disabled, you can choose which desktop to start with at the login screen. Nevertheless, what you are describing doesn’t make much sense to me.