Detect mouse up or end of drag on any scene object

I've been fighting for the better part of a day to get the equivalent of Input.MouseUp(0) in the Editor/scene view.

Basically I need to know when a drag on the root object that contains a scripted object has ended.

The closest Ive come is using a custom Editor on the scripted object but it does not get the events unless it itself is selected and I need it to get an event when the drag of its root is done.

THis is the custom editor solution...

 public class MagnetEditor : Editor {
     public void OnSceneGUI () {
         Debug.Log ("Event="+Event.current);
         if (Event.current.type ==  EventType.MouseUp){
             Debug.Log ("Mouse UP");
         }
 
         
     }
 }

Help?