I'm having problems with Windows Borderless Gaming (WBG).
I've been using it for 7 years or so with no problems outside of a few incompatible titles.
Today, applications are increased in size beyond the resolution I set.

I've figured out it's related to the Windows 10 ease of access settings. There's an option called "Make Everything Bigger" which you can use to increase the size of everything in 25% increments. WBG increased `everything` by a 200-300 pixels at a resolution of 2560x1440, so approximately 25% gave me 3200x1800, tall enough to disappear off the bottom of my screen but not wide enough to reach over the horizontal bounds.

Before I figured that out I updated my GPU driver, changed desktop resolution to a custom 3439x1440, pixel counted to make sure my monitor wasn't lying, and of course have restarted after all changes.

Thought I'd share in case anyone else trips over this.