title: modal popup extender not showing panel on button click
body: <p>I'm trying to use a modal popup extender on my page so when I click a button, it must show a panel.  Here is what I have:</p>
  
  <pre><code>    &lt;asp:UpdatePanel runat="server" ID="updPanel"&gt;
      &lt;ContentTemplate&gt;
          &lt;ajaxToolkit:ModalPopupExtender ID="mpeEmailComplete" runat="server" TargetControlID="btnTesting"
              PopupControlID="pnl" OkControlID="btnOk"
               BackgroundCssClass="modalBackground"&gt;
          &lt;/ajaxToolkit:ModalPopupExtender&gt;
  
  
  
          &lt;asp:Panel ID="pnl" runat="server" style="display:none;"&gt;
              &lt;asp:UpdatePanel ID="udp" runat="server"&gt;
                  &lt;ContentTemplate&gt;
                      &lt;asp:Panel runat="server" ID="pnlEmailComplete" Visible="false"&gt;
                          &lt;asp:Label runat="server" ID="lblTest" Text="Testing testing testing"&gt;&lt;/asp:Label&gt;
                          &lt;asp:Button runat="server" ID="btnOk" Text="OK" /&gt;
                      &lt;/asp:Panel&gt;
                  &lt;/ContentTemplate&gt;
              &lt;/asp:UpdatePanel&gt;
          &lt;/asp:Panel&gt;
  
  
          &lt;asp:Button runat="server" ID="btnTesting" Text="Testing"/&gt;
  
      &lt;/ContentTemplate&gt;
  &lt;/asp:UpdatePanel&gt;
  </code></pre>
  
  <p>but i can't get the panel to popup when the button is clicked.  Anybody know why?</p>