yLink = null;
    static _dummyFromNode = null;
    static _dummyToNode = null;

    commit() {
      const parentv = this.fromVertex;
      if (!parentv) return;
      const routed = parentv.alignment === go.TreeAlignment.Start || parentv.alignment === go.TreeAlignment.End;
      if (this.data && routed) {
        this.link = VirtualizedTreeEdge._dummyLink;
        this.link.fromNode.moveTo(this.fromVertex.x, this.fromVertex.y);
        this.link.toNode.moveTo(this.toVertex.x, this.toVertex.y);
        thi