Since the default borderless windowed mode shows just a black screen, I initially launched the game in fullscreen mode by changing dmc5config.ini:

• FullScreenMode=true
• delete the line FullScreenDisplayMode

Since fullscreen crashes on switching resolution, I switched to windowed mode, which I can fullscreen without problem in stock dwm. Window mode config now looks like this:

• WindowMode=Normal
• FullScreenMode=false Since FullScreenDisplayMode(the resolution) doesn't have fixed values, don't set it manually