Use preference change listener for the enable switch since the user could slide the switch over and onPreferenceTreeClick would not be called.

Change-Id: I917b51cbee558df88fa702299b00bab6ce065319
Add adjustable trigger area for the @ppbar.  Users can define the width, height and Y position of the trigger area.  Only this area will receive touch events. [2/2]

Change-Id: Ie8f80dfc4de5d3de8bcc1a0c24fb6b2aabeeee65