Comment # 5 on bug 1227068 from Tobias Burnus

Trying with *Wayland* after that change:

When kdm has been started without the external screen, i.e. it is only
displayed on the laptop, it is as above: Wayland only has the external screen.

When kdm has been started with both screens available, i.e. showing the
enter-password login on both screens, it shows the startup wheel on the
external screen and then everything gets black and an oversized mouse pointer
is visible that can be moved between external and internal screen; it looks
okay in terms of right/left; at least on the higher-res laptop screen, the
stops half way to the top and it looks as if one can move is far below the
visible screen to the bottom, but I might have missed to spot tip of the mouse
pointer at the bottom of the screen.
– As the keyboard didn't seem to work, I had I rebooted with SysRq +
s(ync),u(nmount),b(oot).