Selectednodestyle property of tree node does not work with iframe

SelectedNodeStyle

<div class="menutree">
<asp:TreeView ID="Treeview1"  runat="server" Target="frame1"  BorderColor="#00CCFF" Font-Bold="False" Font-Italic="False" Font-Size="Large" style="text-align:left" margin-top="200px"  LineImagesFolder="~/TreeLineImages" ImageSet="Arrows">

                           <Nodes>
                              <asp:TreeNode Text="State" Value="Kerala" Expanded="True" >
                                 <asp:TreeNode Text="Kerala" Value="Kerala" Expanded="False">
                                    <asp:TreeNode Text="Kerala Boundary" Value="KeralaBoundary" NavigateUrl="~/Output.aspx"   Target="frame1"></asp:TreeNode>
                                    <asp:TreeNode Expanded="False" Text="Administrative Division" Value="KeralaAdministrative ">
                                       <asp:TreeNode Text="Rural" Value="Rural" Expanded="False">
                                          <asp:TreeNode Text="Block Panchayat" Value="BlockPanchayat" NavigateUrl="~/WebForm3.aspx" Target="frame1" ></asp:TreeNode>
                                          <asp:TreeNode Text="Grama Panchayat" Value="GramaPanchayat" ></asp:TreeNode>
                                       </asp:TreeNode>
                                       <asp:TreeNode Text="Urban" Value="Urban/" Expanded="False">
                                          <asp:TreeNode Text="Municipality" Value="Municipality" ></asp:TreeNode>
                                          <asp:TreeNode Text="Corporation" Value="Corporation" ></asp:TreeNode>
                                       </asp:TreeNode>
                                    </asp:TreeNode>
                                    <asp:TreeNode Expanded="False" Text="Revenue Division" Value="KeralaRevenue">
                                       <asp:TreeNode Text="Rural Area" Value="Rural" Expanded="False">
                                          <asp:TreeNode Text="Taluk" Value="Taluk" ></asp:TreeNode>
                                          <asp:TreeNode Text="Village" Value="Village" ></asp:TreeNode>
                                       </asp:TreeNode>
                                       <asp:TreeNode Text="Urban Area" Value="Urban" Expanded="False">
                                          <asp:TreeNode Text="Municipality" Value="Municipality" ></asp:TreeNode>
                                          <asp:TreeNode Text="Corporation" Value="Corporation" ></asp:TreeNode>
                                       </asp:TreeNode>
                                    </asp:TreeNode>
                                 </asp:TreeNode>
                               </asp:TreeNode>
                           </Nodes>
                           <NodeStyle  Font-Names="Verdana" Font-Size="Small" ForeColor="Black" HorizontalPadding="5px" NodeSpacing="0px" VerticalPadding="0px" />
                           <HoverNodeStyle  Font-Underline="True" ForeColor="#5555DD"/>
                           <ParentNodeStyle Font-Bold="False" />
                           <SelectedNodeStyle Font-Bold="true" />
</asp:TreeView>
 </div>
<asp:Panel ID="Panel1" runat="server">
                        <div class="iframeclass">
                            <iframe width="957" height="600"  name="frame1"  id="frame1" ></iframe>
                        </div>
</asp:Panel>