Arrow Key Moves the Cursor

When you add a building component and press an arrow key to rotate the component in the xy plane, the component rotates, but the cursor also moves in the direction of the arrow.

Check if you have Microsoft Paint running. Paint has a feature that allows you to move the cursor using the arrow keys. Sometimes the function stays on and controls the cursor even when Paint is minimized. For example, when you rotate a component 5 degrees with the up arrow key, the component rotates, but the cursor also jumps up. The problem is solved by closing all Microsoft Paint windows.