So. Before I installed the mod, I could play the game in Windowed-Borderless mode, with the resolution set to 2560x1440 while the game still taking up 100% of the space on my 4k (3840x2160) monitor. So it would basically be like playing in fullscreen with 2560x1440 as the resoultion. Now when I try to play in Windowed-Borderless mode with the resolution set to 2560x1440, it does not take up the entire screen. Yes, I know I could just play in fullscreen with 2560x1440 as the resolution, but it's a pain to switch windows.
Here is a screen shot of how it is now, if it helps.