Kodi 17.1 on Opensuse 42.2 – force display detection

Hello around!

First post here an need some help please.

Got a new used notebook (Thinkpad X230) and installed Opensuse 42.2. On the miniDisplay port I connected a 22` Display. Opensuse recognises the second Monitor and the resolution is on 1920×1080 50hz. KDE Desktop is running also on the second display with no problems.

here comes the problem:
When I launch Kodi 17.1 on the second display it only runs in the resolution of the main notebook display 1366×768 and I couldnt find a way to change the resolution – so most of the 22` display stays black. Monitor output in kodis video settings is set to default – if I change it to hdmi1 either the second monitor display goes black or kodi switches back to the display of the notebook and that one goes black.

I tried to delete everything and set it up again – no change.

It seems to me that kodi doesnt really recognise the 2 monitor.
On my old broken notebook (Edge13) with a older version of Opensuse (11.3) everything worked without problem.

how can I force Kodi to recognise the second display properly?

I´m glad for any help!