Adding The Same TreeNode To Two Nodes In A TreeView

When I attempt to run the following code:

protected void NavigationTreeView_TreeNodePopulate(object sender,
TreeNodeEventArgs e) {
TreeNode tn1 = new TreeNode("node1","node1");
TreeNode tn2 = new TreeNode("node2", "node2");
TreeNode newNode = new TreeNode("add me to both nodes", "add me to
both nodes");
e.Node.ChildNodes.Add(tn1);
e.Node.ChildNodes.Add(tn2);
tn1.ChildNodes.Add(newNode);
tn2.ChildNodes.Add(newNode);
}

It does not behave as expected. Instead of adding a copy of newNode to each
of the other two nodes, it adds to tn1 and then when it adds it to tn2 it
removes it from tn1, thus in the end only tn2 has the newNode and tn1 has no
children. How can I add the same node to two separate locations in a treeview?