New to Ajax - my first Test Form not behaving as expected

Hello - 

I'm new to AJAX and going through an example in a book. It's a very simple exercise which I was hoping to evolve into something real-world. 

Problem is my panel know as pnlConfirmation is not being displayed once the timer runs out.  When I click the button and fire the event, the UpdateProgress panel does show as expected but once it's done, pnlConfirmation is not displayed. I was hoping for a second set of eyes to point of the obvious error.  Thanks!!

<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>

<asp:UpdatePanel ID="UpdatePanel1" runat="server"><ContentTemplate><asp:Panel ID="pnlForm" runat="server"><br /><br /><asp:Button ID="Button1" runat="server" Text="Do something awesome" OnClick="Button1_Click" /></asp:Panel></ContentTemplate></asp:UpdatePanel><asp:UpdateProgress ID="UpdateProgress1" runat="server" AssociatedUpdatePanelID="UpdatePanel1"><ProgressTemplate><asp:Panel ID="pnlProgress" runat="server"><br /><br />
            Doing something awesome now.....<br /><br /></asp:Panel></ProgressTemplate></asp:UpdateProgress><asp:Panel ID="pnlConfirmation" runat="server" Visible="False"><br /><br />
         Something awesome was done.<br /><br /></asp:Panel>

...and...the button's click event (C#):

    protected void Button1_Click(object sender, EventArgs e)
    {
        pnlConfirmation.Visible = true;
        pnlForm.Visible = false;
        System.Threading.Thread.Sleep(5000);

    }

What am I doing wrong?