Resolution and Widget size problem for 1/3 client

Hi, when loading my main menu level it seems that the resolution and/or widget gets scaled up. This is only done by one of the 3 clients and I don’t know why that is. Even if i just start the level from start directly from the editor I will have the problem that one clients screen gets scaled up and the other two is as predefined sizes. Does anyone has a clue of why that is? As you can see in the image below Client 1 and Client 3 has their Map loaded with the screen keeping its says along with the widget. Client 2 however got scaled up shows a black background except from the top left corner where the scaled up widget can be seen.