var merge = oldnode.layout.mergeNode;
        if (merge) {
          var it = merge.findLinksOutOf();
          while (it.next()) {
            var link = it.value;
            if (link.fromNode.containingGroup !== link.toNode.containingGroup) {
              dropOntoLink(e, link);
              break;
            }
          }
        }
      } else if (oldnode instanceof go.Node) {
        var cat = oldnode.category;
        if (cat === 'Merge' || cat === 'End' || cat === 'EndFor' || cat === 'EndWhile' ||