Run the check
Leave the mouse untouched and watch for movement in the test.
Disconnect one additional pointing device or controller at a time.
Check whether remote-control software or touch input is active, then repeat.
Read the result
Movement that stops with one input source identifies a useful next check.
Limits and next step
The page cannot identify the physical source of a pointer event.
Repeat the check after changing one setting or connection. Keep a record of what changed before deciding whether the device needs service.