resoloution not saving

my computer is a total potato, I have to run the lowest settings possible with vehicle collision off to even play, im looking to get a new computer soon but that isn't the point. I play beamng in 680x480 4:3 60hz for best framerate while doing time attacks, I do this in fullscreen mode, but every time I alt-tab to do anything like change music or look at the time it resets my resoloution and screen type, it also resets on game startup, is there a way to lock the game to a fixed resoloution and window type?