ng complete subtree
    function collapseTree(node, portid) {
      node.findLinksOutOf(portid).each((l) => {
        l.visible = false;
        var n = l.getOtherNode(node);
        if (n !== null) {
          n.visible = false;
          collapseTree(n, null); // null means all links, not just for a particular portId
        }
      });
    }

    // get the text for the tooltip from the data on the object being hovered over
    function tooltipTextConverter(data) {
      var str = '';
      var e = myDia