Apple - Mouse hover doesn't work when Microsoft mouse is connected

I know it's an old thread but since there are no solution mentioned for the Microsoft Sculpt Ergonomic Mouse... I had the same problem and fixed it just now.

It is a hardware issue where the little button below the Windows blue button gets stuck. I had two of these and the one where it was clickable, it worked fine and the second one had the button stuck and the hover over wasn't working. I stuck a push pin into it and tried to pry it out through the rubber layer on it and it now works fine.

So it was down to poor quality buttons on this nice mouse.

This is most likely your mouse failing, which is not related to the changes you made. It seems that the mouse is only reporting the cursor location when it is clicked, and the fact that a webpage shifts horizontally when the dongle is plugged and unplugged and the mouse is not being moved is a sign that the mouse is sending false information to the computer.

Before you get a new mouse, try replacing the batteries in all of your wireless mouse/keyboard devices, and try using a different mouse in case it is a problem with the computer.