resolution problem - unable to fullscreen below standard resolution

Hey, I generally play on 1280 x 800 resolution Fullscreen. It's a nice concise viewing area that allows me to control my champion optimally. Recently, I can no longer play on fullscreen with this resolution setting as it does not actually go fullscreen, it just gets surrounded by some black screen.

I know most people would just adapt their resolution to standard, but this really changes the camera view and affects my gameplay. It's not worth looking better graphically to play on a zoomed camera with tiny UI, where there is way too much to keep track of on-screen.

I hope that this error can be fixed, so that people like me have the option of playing on non-standard resolutions. I know this isn't the "usual" setting and so most players couldn't care less, but I can't see myself adjusting to a massive amount of map on-screen.