If you do not delete the tree node and BuildTree

[peniiii]

---------------Page_Load-----------
if (!IsPostBack && !X.IsAjaxRequest)
{
init();
this.BuildTree(tree_myapproval.Root);
}

---------------TreePanel BuildTree-----------
private void BuildTree(Ext.Net.NodeCollection nodes)
{
if (nodes == null)
{
nodes = new Ext.Net.NodeCollection();
}
Ext.Net.Node root = new Ext.Net.Node();
root.Text = "결재경로 설정";
root.Expandable = true;
root.Icon = Icon.ChartOrganisation;
root.Expanded = true;
root.EmptyChildren = true;
nodes.Add(root);
}

------------------button click treepanel remove Listeners------------
var clear_tree = function (tree)
{
var root = tree.getRootNode();
while (root.childNodes.length > 0) {
root.removeChild(root.childNodes[0]);
}
}

??????????????
button click remove after reBuildTree -> BuildTree(tree_myapproval.Root)
Not shown in the tree ㅜㅜ