A user has been waiting since January of this year for a promised update to JP that would use a double-click of the play/pause headset button to cause a next track action. Thanks, Nicholas, for your patience. I have implemented this. I’ve also added a triple-click for doing a previous track action. It sounds like this is a standard feature of other apps–including the stock Android music player. It’s not something I was aware of, but it is a useful feature.