I have an ultrawide monitor with a basic single horizontal split down the middle. Sometimes when I maximize an app in either split and then position my mouse over the outer edge of the window, the window will instantly move several pixels away from the outer edge (as if I had resized it). I can then maximize back to the full split but then it resizes itself again when I move the mouse back near the edge again. I can only reproduce this with certain apps, including Chrome, Edge, and other UWP apps. Chrome and Edge are the major problems (usually on the right-hand split due to the horizontal scroll bar). I have DisplayFusion running on a separate computer with the exact same monitor (and mouse), but do not ever experience this there. Both machines are running win10 21H2 -- the only difference I can point out is that the BAD computer is connected via HDMI and the GOOD computer via display port. I have already tried uninstalling/reinstalling, any other tips are appreciated. Thanks,

probably should have mentioned that the BAD computer is an Intel Iris Xe equipped laptop (HDMI to external monitor), whereas the GOOD computer is a desktop with an nvidia 1660. I actually disconnected the external monitor from the bad laptop and was able to duplicate the problem with the same split configuration on the native display.

I figured this out!! It's called "Lenovo Auto Scroll" and it absolutely sucks!!

Just disabling the service was not enough -- once I fully uninstalled and restarted the problem was gone. Hope this helps anyone else in similar situation