Launch the executable using the switches -screen-fullscreen 1 -screen-width <horizontal_res> -screen-height <vertical_res>
This worked for me. The app was working a week or 2 ago but a Win 10 update messed it up. The app would start but only in a small window that wouldn't maximize. The screen resolution was set to1920x1080 so I filled in those values for the command line parameters and it worked full screen.
Also, I found that after running the first time I could take out the added parameters and it still worked full screen.
Of course it works all the time with no problems in Linux :D