public Component getTreeCellRendererComponent(
        JTree tree,
        Object value,
        boolean selected,
        boolean expanded,
        boolean leaf,
        int row,
        boolean hasFocus) {

      Component c =
          super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, hasFocus);

      if (value instanceof VariableNode) {
        VariableNode node = (VariableNode) value;
        tooltipText = node.getToolTipText();

        if (node.var instanceof Structure) {
          Structure s = (Structure) node.var;
          setIcon(structIcon);
          tooltipText = s.getNameAndAttributes();
        } else tooltipText = node.getToolTipText();
      } else if (value instanceof DimensionNode) {
        DimensionNode node = (DimensionNode) value;
        tooltipText = node.getToolTipText();
        setIcon(dimIcon);
      } else if (value instanceof GroupNode) {
        GroupNode node = (GroupNode) value;
        tooltipText = node.getToolTipText();
      }

      return c;
    }
  /**
   * Set the currently selected Variable.
   *
   * @param v select this Variable, must be already in the tree.
   */
  public void setSelected(VariableIF v) {
    if (v == null) return;

    // construct chain of variables
    List<VariableIF> vchain = new ArrayList<>();
    vchain.add(v);

    VariableIF vp = v;
    while (vp.isMemberOfStructure()) {
      vp = vp.getParentStructure();
      vchain.add(0, vp); // reverse
    }

    // construct chain of groups
    List<Group> gchain = new ArrayList<>();
    Group gp = vp.getParentGroup();

    gchain.add(gp);
    while (gp.getParentGroup() != null) {
      gp = gp.getParentGroup();
      gchain.add(0, gp); // reverse
    }

    List<Object> pathList = new ArrayList<>();

    // start at root, work down through the nested groups, if any
    GroupNode gnode = (GroupNode) model.getRoot();
    pathList.add(gnode);
    Group parentGroup = gchain.get(0); // always the root group

    for (int i = 1; i < gchain.size(); i++) {
      parentGroup = gchain.get(i);
      gnode = gnode.findNestedGroup(parentGroup);
      assert gnode != null;
      pathList.add(gnode);
    }

    vp = vchain.get(0);
    VariableNode vnode = gnode.findNestedVariable(vp);
    if (vnode == null) return; // not found
    pathList.add(vnode);

    // now work down through the structure members, if any
    for (int i = 1; i < vchain.size(); i++) {
      vp = vchain.get(i);
      vnode = vnode.findNestedVariable(vp);
      if (vnode == null) return; // not found
      pathList.add(vnode);
    }

    // convert to TreePath, and select it
    Object[] paths = pathList.toArray();
    TreePath treePath = new TreePath(paths);
    tree.setSelectionPath(treePath);
    tree.scrollPathToVisible(treePath);
  }
 private void addUsageNodes(
     @NotNull GroupNode root,
     @NotNull final UsageViewImpl usageView,
     @NotNull List<UsageNode> outNodes) {
   for (UsageNode node : root.getUsageNodes()) {
     Usage usage = node.getUsage();
     if (usageView.isVisible(usage)) {
       node.setParent(root);
       outNodes.add(node);
     }
   }
   for (GroupNode groupNode : root.getSubGroups()) {
     groupNode.setParent(root);
     addUsageNodes(groupNode, usageView, outNodes);
   }
 }