Removing DragListener "this listener's node" references, since we can add the listener to multiple nodes, see https://github.com/phetsims/scenery/issues/131
Removing DragListener "this listener's node" references, since we can add the listener to multiple nodes, see https://github.com/phetsims/scenery/issues/131

phetsims/scenery,phetsims/scenery,phetsims/scenery