So, I've been trying to figure this out for the last two days. Google, looking into SDL source code (video/SDL_video.c, specifically), as well as libXrandr source code. I'm expecting two displays returning 1920 x 1080 each, so that my window which I create with SDL_WINDOW_FULLSCREEN_DESKTOP won't span the entire desktop, but just the one screen. I've got a main development machine with two monitors where this works as expected, but this machine with two monitors somehow regards both monitors as being part of one display.
I was wondering if anyone had any idea on how I could get SDL_WINDOW_FULLSCREEN_DESKTOP to just work on one window instead of blowing up to both windows. Thanks.