Comment # 11 on bug 1208990 from Andreas

(In reply to Takashi Iwai from comment #10)
> And you're running X11, not Wayland, right?
Leap 15.5 with Gnome on X11 and Wayland works well.

> Just to be sure, can you check whether you can start the fallback (icewm)
> session (selected at login on display manager) with the same monitor
> configuration you've seen the problems on the installer?
I don't have IceWM installed because I unchecked it before installing Leap. It
doesn't work well with a 4K display

> If this works on the installed system while not on the installer, something
> must be missing in the installer.
Yes, after loading drivers Yast GUI installer fails to start
https://bugzilla.opensuse.org/attachment.cgi?id=865313
It failback to text mode, but you can only see it on external monitor. 
https://bugzilla.opensuse.org/attachment.cgi?id=865315
After clicking on "OK", Yast appears in text mode, very small with 4K
resolution.

At 30 seconds you can see this place with a error in the photo above, but in
the video Yast is starting.
https://youtu.be/pohDXspaMuE?t=30

> Judging from hwinfo, nouveau is still used.  So that should be same as on
> installer, at least...
Yes, right now I can't use the proprietary nvidia driver on Leap 15.5
https://bugzilla.opensuse.org/show_bug.cgi?id=1209067