Windows10 Fullscreen Exclusive Mode - not working

We are not able to get any of our windows maschines to get TD to run in Fullscreen Exclusive Mode.

I searched the internet up and down. And could not find any solution.

I run the demo file in borderless fill mode but windows will not switch to Fullscreen Exclusive Mode.

We are running a project for the client with 3840x2160@50hz NotchLC Video and we are seeing micro stuttering. everything is set uo to 50hz correctly.
So I think only solution is Fullscreen Exclusive Mode. But no chance.

So I tried it on a simple win10 maschine with the demo project on 60Hz and the same.

How to get Fullscreen Exclusive Mode up and running with TD

This to know would be so helpfull.

Best jnlab