Should there be light coming from the tracking hole of a properly functioning Magic Mouse, or is the illuminating source invisible (eg. infrared)? My Magic Mouse seems less smooth and responsive than I recall it being when I first got it. When I tried to check it out to see if, for example, there was dust in the hole where the laser is located, I noticed that there was no visible light coming from there. When I placed it flat on a table and looked underneath...still no visible light. Could it still function without an operational laser (for example, if the optical sensor is working off relatively dim room light and not the laser)? I recall there being a thread here where someone asked about the safety of the light shining from the tracking hole. So I presumed that during normal operation the laser light should be visible under the mouse. Thanks in advance for your help.