Comment # 18 on bug 1046664 from Bj�rn Lie

(In reply to Simon Herrmann from comment #16)
> not a duplicate anymore because the problem on Leap 42.3 is solved but
> tumbleweed this does not see my external monitor right now.

Lets see what happens when running on wayland.

Please install gnome-session-wayland, and ensure that /etc/gdm/custom.conf

does not have WaylandEnable=false set/not commented out with a #

After that, reboot, and select GNOME on the cog wheel in gdm.