is this from the repos slide2answer? if yes,

1. how come the slide comes with also the reject and answer button at the same time? isn't it a little bit redundant?
2. Maybe replace those buttons with a mute or some other buttons to complement the slider?
3. is the proximity sensor toggling on/off causing the default-ui to be laggy sometimes? if so, then this would make it more responsive right?

I think this is a great addition if using this would make the phone-ui better.