Samsung LC32G7xT not working in Game Mode but fine in Desktop Mode

[Looser]

My Samsung LC32G7xT is working fine in in Desktop Mode, starting Steam from Desktop Mode let´s me play my games without problem. In Game Mode the Samsung LC32G7xT goes gray and the Steam Deck Screes goes black, just as if Steam Deck has detected an external Monitor. Steam Deck is docked in offical Steam Dock. I tried another external Monitor with full HD resolution, there both Gaming Mode and Desktop Mode worked. So my conclusion would be Steam Deck has a problem with Samsung LC32G7xT.