Issues with mouse capture/keeping the mouse in the game window

It seems that no matter what I do, if the player moves the mouse all the way to the right, regardless of whether the mouse cursor is being shown, it goes very slightly out of the game window, and if the player clicks while it’s there they start resizing the window rather than interacting with the game. This happens when I pack the game and run it as its own process, and also when I choose ‘Standalone Game’ when testing in the editor, but not when I just play it in a new editor window. Anyone have any ideas how I could get around this?

So, I figured out that changing the custom scaling in my PC’s display settings seems to have fixed the issue. I have a 4K monitor that I usually have set at 200% scaling, and it’s caused issues with certain programs before, but this is the first time I’ve had this particular problem with UE4. Changing back to 100% stopped it, but does anyone have any other possible solutions? I know how frustrating it is to have a program that doesn’t want to work with scaling, I’d rather not publish one myself.