I've had the same issue as gavlarN, and was able to learn some things.
I've got dual screens, 4k at 150% scaling and 2560x1600 at 125% scaling.
I installed with 32 bit in place, 32 bit set to full screen; exclusive mode; DirectX 9; vsync on
1st run, I got a display much larger than screen size then it shrank to a squished form only 2/3rds high but wider than the 4k screen. A first I though I couldn't click with the mouse, only type. Then I realized I could click at the top of the screen, played a bit and realized the 'click' zone and displayed cursor were not aligned. The 'mouse' coords