public void removeRoot(Url url) {
    RepositoryTreeRootNode root = (RepositoryTreeRootNode) getRoot();
    for (int i = 0; i < root.getChildCount(); i++) {
      RepositoryTreeNode node = (RepositoryTreeNode) root.getChildAt(i);
      if (node.getUserObject().equals(url)) {
        root.remove(node);
      }
    }
  }
public void removeRoot(Url url)