ks between snapped ports,
    // and remove obsolete links because their ports are no longer coincident.
    doDropOnto(pt, obj) {
      super.doDropOnto(pt, obj);
      // Need to iterate over all of the dropped nodes to see which ports happen to be snapped to stationary ports
      const coll = this.copiedParts || this.draggedParts;
      const it = coll.iterator;
      while (it.next()) {
        const node = it.key;
        if (!(node instanceof go.Node)) continue;
        // connect all snapped ports o