public DefaultMutableTreeNode addFile(VirtualFile file) {
    final DefaultMutableTreeNode root = (DefaultMutableTreeNode)myTree.getModel().getRoot();
    final DefaultMutableTreeNode treeNode = createFileNode(file);
    root.add(treeNode);
    DefaultTreeModel model = (DefaultTreeModel)myTree.getModel();
    model.nodeStructureChanged(root);

    return treeNode;
  }
public DefaultMutableTreeNode addFile(VirtualFile file)