Check your UI Scale setting. Has to be exact on both or the clicks are off. :P Also, Skarlot is right about the resolution not mattering, EXCEPT that the resolution aspect ratio must be the same. If you use one box on 1024x768(1.33~ aspect ratio) and one at 1920x1200(1.6 aspect ratio), the clicks will be off. So, for a quick reference, here's the list of common resolutions and their aspect ratios.