> But if it's windowed then it should be impossible.
I worked on several apps for the visually impaired that automatically move the mouse cursor to different UI elements in the front-most application, regardless of the window state. It’s a good reminder that “impossible” often just means “I haven’t accounted for that use case yet.”
If it's part of the OS's standard accessibility framework then it's acceptable. The important point is that applications shouldn't be able to arbitrarily move the mouse in situations when it's unexpected.