Actually I don't think this is a Trinity problem, because reverting to lightdm 
shows no change, but I post this in hope someone can give me a clue:

I have setup a machine based on an Intel based SBC (UP board with a "cherry 
trail" processor. It runs openSUSE Leap and Trinity. I initially had lots of 
screen corruption but this I solved by setting the graphics to "xua".

My problem is this: while I have the screen resolution setup to 1920x1080 (and 
trinity desktop looks OK for this resolution), the monitor (which is accessed 
from HDMI through an HDMI to VGA converter because I use a KVM that needs VGA 
connectors) was initially "seen" as 1024x768.

And the applications seem to retain that resolution. I could make things 
better in kmail (which is the main application for this machine) by reducing 
the font size. The other applications still look "too big".

So I get the feeling that the lower resolution was saved somewhere...

Is there a place where I can tell them to use 1920x768?

Have good day,

Thierry