public virtual void UnregisterOnUnlatch(TouchLatchUnlatch d) 
 {
     OnUnlatch-=d;
 }
 /// <summary>
 /// Called when a finger has unlatched
 /// </summary>
 public virtual void RegisterOnUnlatch(TouchLatchUnlatch d) 
 {
     OnUnlatch-=d;
     OnUnlatch+=d;
 }