Yeah I was wondering when that mouse detection issue was going to show up! Might I ask, where you running the game at 4K? I've always had issues with the mouse hit detection in SDL when the window is ran at a resolution than where it's intended. I did come up with a fix where I divided the intended resolution with the current one and then divided that result by the current mouse position. It's not accurate (since you know) and I think it might be the conversion from floating point to integer that may be screwing things up. This one I shall kick myself for, since I thought transferring that to a integer would work consistently. Sorry about that, it'll probably work better if you ran it in 1440P, but I'll fix that issue right away! Thank you for making of aware of it!