w go.Node('Auto', {
      locationSpot: go.Spot.Center,
      // on mouse-over, highlight the node
      mouseDragEnter: (e, node) => (node.isHighlighted = true),
      mouseDragLeave: (e, node) => (node.isHighlighted = false),
      // on a mouse-drop add a link from the dropped-upon node to the new node
      mouseDrop: (e, node) => {
        const newnode = e.diagram.selection.first();
        if (!mayConnect(node, newnode)) return;
        const incoming = newnode.findLinksInto().first();
        if (in