Expanding a collapsiblepanelextender with an invisible link?

ASPX:
 
<div id="OpenButton">
 
     <asp:LinkButton ID="lnkOpen" runat="server" OnClick="lnkOpen_Click" Width="136" Height="145" CssClass="OpenButton" />
 
</div>
 
<div id="onpage_menu_wrapper">
 
     <asp:UpdatePanel ID="OnPageMenuUpdatePanel" runat="server" UpdateMode="Conditional">
 
          <Triggers>
 
               <asp:AsyncPostBackTrigger
 
                  ControlID="lnkOpen"
 
                  EventName="Click" />
 
         </Triggers> 
        <ContentTemplate>
 
             <asp:Panel ID="pnlDefault" runat="server" visible="true">
 
                     <<<<Default content here  >>>>>
 
            </asp:Panel> 
            <asp:Panel ID="pnlMenuOptions" runat="server">
 
                 <asp:HyperLink ID="lnkExpand" runat="server" Text="Expand" CssClass="headlineTitle"></asp:HyperLink>
 
            </asp:Panel>
 
        <AjaxToolkit:CollapsiblePanelExtender 
       ID="collapseMenu"
 
       runat="server"
 
       TargetControlID="pnlMenu"
 
       ExpandControlID="lnkExpand"
 
       Collapsed="true"
 
       SuppressPostBack="True"
 
       CollapseControlID="lnkExpand">
 
    </AjaxToolkit:CollapsiblePanelExtender> 
    <asp:Panel ID="pnlMenu" runat="server" Height="0px">
 
           <<<<Menu Content Here>>>>
 
    </asp:Panel>
-----------------------------------------------------------------------
Here's my c# code behind:
 
protected override void OnLoad(EventArgs e) 
{
 
     base.OnLoad(e); 
     Page.Header.DataBind();
 
}
 
 
 
protected void Page_Load(object sender, EventArgs e) 
{
 
     if (!IsPostBack) 
     {
 
           //set the visibility of the menu panel
 
           pnlMenuOptions.Style.Add(HtmlTextWriterStyle.Display, "none"); 
      }
 
}
 
protected void lnkOpen_Click(object sender, EventArgs e) 
{ //open the menu
 
     pnlMenuOptions.Style.Remove(HtmlTextWriterStyle.Display); 
     pnlMenuOptions.Style.Add(HtmlTextWriterStyle.Display, "block");
 
     pnlDefault.Style.Add(HtmlTextWriterStyle.Display, "none"); 
}
 
Thanks again.

                                  

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:
78:
79:
80:
81:
82:
83:
84:
85:
86:
87:
88:
89:
90:
91: