election.first();
        if (!newnode) return;
        if (!(newnode instanceof go.Group) && newnode.linksConnected.count === 0) {
          // when the selection is dropped but not hooked up to the rest of the graph, delete it
          e.diagram.removeParts(e.diagram.selection, false);
        } else {
          e.diagram.commandHandler.scrollToPart(newnode);
        }
      },
      'undoManager.isEnabled': true
    });

    // dragged nodes are translucent so that the user can see highlighting of links