Thank you for the answer, seems you have the exact same tool as me with the settings that are standard at grundmods: backbuffer on, maxwindow deactivated, improved fps limiter, no direct draw, high dpi on, dxwind off. Right?
Well i copied both files into dune2000 order with no effect. I will still try some combinations. The thing is CnCnet patch changes Dekstop Resolution before starting the game, so Red Alert will be depicted in full screen with just small black borders. Other games like Dune 2 in DosBox can also not be shown in Fullscreen.