I’m trying to add the Gnome and KDE desktops as choices on the LightDM login screen, but it doesn’t seem to be happening. I’ve run searches, all that say to use lightdm-settings or lightdm-gtk-greeter-settings, neither of which has the option to add the option to login to a different desktop (I’m currently on XFCE, but have both Gnome and KDE installed). I have a /etc/lightdm/lightdm.conf file, but when I try to go into it to edit it to add the options, the file is very long and pretty much all greek to me. I can post it if need be. The lightDM login screen has no options to say that I’d like to login to Gnome or KDE, there is no button to push for it, anything. It just has user and password, that’s it.
How can I do this? I use (although XFCE is my default desktop) different desktops for different things at times, and having to run sudo systemctl disable lightdm and sudo systemctl enable gdm every time I’d like to run Gnome (and vice-versa to go back to XFCE) is taxing.
Thanks so much!
Sorry, I’m wondering if KDM would do this for me?
Hi Kim,
I can’t speak for LightDM, but I can speak for SDDM and GDM. I have used both to login to both GNOME w/X11/Wayland and KDE w/X11/Wayland. I moved from GDM to SDDM about 3-6 months ago. I only use SDDM (I use X11 still).
It worked without much or any intervention on my part other than having all the GNOME and KDE desktop packages installed. I have changed very few SDDM options from default because of my use of X11.
I went from GNOME to KDE and I used a dnf group install for the KDE packages. then I went and found more KDE apps/packages I wanted and installed them afterwards.
I can’t speak to XFCE as I am not a user of it, but my expectation would be that it would work with SDDM if all the right parts/packages were installed.
Well, other than disabling one and enabling the other:
sudo systemctl disable gdm
sudo systemctl enable sddm
Sorry about that…
That’s fine, I gotcha. 
It turns out I was looking in the wrong place on the screen for it. The problem now, is LightDM crashes and goes to tty when I choose a different desktop, and it doesn’t include KDE. Just Gnome. I’m going to have to look into this more.
Thank you!
Lightdm usually has a desktop selection button in the upper right part of the screen.