TreeView on Master Page

I have a treeview setup on my masterpage.  Whenever I click on a link in the treeview, the page is reloaded with the correct information.  However, the tree is fully collapsed.  I'm trying to keep the tree opened to the node that was clicked on.  Can anyone help?

Here is what the TreeView code looks like in MasterPage.master:
<asp:TreeView ID="TreeView1" runat="server" ImageSet="Arrows" ExpandDepth="1" NodeWrap="True" DataSourceID="SiteMapDataSource1" NodeStyle-CssClass="treeNode" RootNodeStyle-CssClass="rootNode" LeafNodeStyle-CssClass="leafNode" EnableViewState="False" OnTreeNodeDataBound="TreeView1_TreeNodeDataBound" Font-Size="10pt" OnSelectedNodeChanged="TreeView1_SelectedNodeChanged" > <LeafNodeStyle CssClass="leafNode" ...