Gestures not working

[Vetdoctor]

I activated the gestures with the hope of being able to answer my phone hands free when it's lying on the desk next to me at work but no go. Swipe my hand fast or slow, high or low it just doesn't matter. The phone sees me, I can see the green pickup icon wobble when I motion but only rarely does it actually open the phone. Is this working for others? Is there some secret gesture to get this to work?