ajaxToolkit:ToolkitScriptManager Causing Buttons On Page To Become Non-functional

I am running IE 9 with compatibility mode turning on. I am using the .NET V4.0 framework.

I use the ToolkitScriptManager on a page in conjunction with the CalendarExtender.When these are in the CodeBehind the other buttons on thepage do not work. The page just sits there. It does not go through the PostBack for the page. I know this because in the context in which I am working I use the Debug.Print to issue a message at the beginning of the Page_Load event and I am not getting that message. I do get the message when the page is first loaded, but, as I said, on the PostBack there are no messages created.

When Icomment out everything referencing the CalendarExtender except the Regiser Assembly,the buttons work.

<%@ Page Title="HCAD - Online Agent Services" Language="VB" MasterPageFile="~/Page.Master" AutoEventWireup="false" 
    CodeFile="AgentDocket.aspx.vb" Inherits="Hearing_AgentDocket" %><%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>

When I add the following codethe buttons stop working.

<ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"></ajaxToolkit:ToolkitScriptManager>

More detail code below:

<%@ Page Title="HCAD - Online Agent Services" Language="VB" MasterPageFile="~/Page.Master" AutoEventWireup="false" 
    CodeFile="AgentDocket.aspx.vb" Inherits="Hearing_AgentDocket" %><%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %><asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" Runat="Server"></asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server"><script type="text/javascript" language="JavaScript">

        function change_cursor(cursor_type) {
            if (cursor_type == "") cursor_type = "default";
            document.body.style.cursor = cursor_type;
            return (true);
        }

    </script><ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"></ajaxToolkit:ToolkitScriptManager><!--  BODY STARTS HERE  --><div id="divPageTitleBackground"><div id="divPageTitle"><asp:Label ID="lbl_Heading1" CssClass="title CenterObject" Width="100%" runat="server"></asp:Label><br /></div><div id="divPageTitleNavigation"><div style="position:relative;width:50%; float:left; margin-top:0px;z-index:2;"><asp:Button Visible="false" ID="btnHome3" CssClass="buttonStandardDefault" runat="server" Text="Home" Font-Names="Arial" Font-Bold="true" /></div><div style="position:relative;width:50%;text-align:right;float:right; margin-top:0px; padding-left:0px;z-index:3;"><asp:Label ID="Label9" BackColor="transparent" runat="server" Text="Label">&nbsp</asp:Label></div></div></div><!-- End of divPageTitleBackground--><%--<div class="div4pxHorizontalLine"></div>--%><asp:HiddenField ID="hf_Agt" runat="server" />    <asp:HiddenField ID="hf_User" runat="server" /><asp:HiddenField ID="hf_pwd" runat="server" /><asp:HiddenField ID="hf_hcadpwd" runat="server" /><asp:HiddenField ID="hf_FindAcct" runat="server" /><asp:HiddenField ID="hf_Validated" runat="server" /><asp:Panel ID="Panel_LoginError" runat="server"><span class="headline">Agent Login Error<asp:Label ID="lbl_AgentError" runat="server" Text="Agent Login Error"></asp:Label>        </span><p><asp:Label ID="lbl_AgtUnknown" runat="server"></asp:Label></p>        <p><asp:Label ID="lbl_ToRegister" runat="server"></asp:Label></p>        </asp:Panel>  <%--<asp:TextBox ID="TextBox1" ToolTip="Enter Date Only (no time value)" runat="server" Font-Size="8" Width="60px" maxlength="10"></asp:TextBox><ajaxToolkit:CalendarExtender TargetControlID="tb_txt_Meeting_Date_From" ID="CalendarExtender3" runat="server"></ajaxToolkit:CalendarExtender>--%><asp:Panel ID="Filter_Panel" runat="server" ><div class="box" style="width:97%; z-index:10; padding: 4px 8px 0px 8px; margin:auto auto auto auto; "><div class="corner TL "></div><div class="corner TR"></div><%--<div class="corner BL"></div><div class="corner BR"></div>--%><table id="Table2" width="100%" border="0" style="text-align:center" cellpadding="0" cellspacing="0"><tr><td valign="middle" align="right" style="width:28%; color:black; font-weight:bold; font-size:7pt; margin-left:8px; ">Filter:</td><td valign="bottom" style="width:29%; color:black; font-weight:bold; font-size:7pt; margin-left:8px; "><table id="firsttbl" width="100%" border="1" style="text-align:center" cellpadding="0" cellspacing="0"><tr><%--                            <td align="center" class="css_gvHeaderStyle" style="font-weight:bold; width:15%;"><asp:Label ID="lblAgent" runat="server" Font-Size="7pt" Text="Agent"></asp:Label></td>--%><td align="center" class="css_gvHeaderStyle" style="font-weight:bold; width:36%;"><asp:Label ID="Label2" runat="server" Font-Size="7pt" Text="Type"></asp:Label></td><td align="center" class="css_gvHeaderStyle" style="font-weight:bold; width:64%;"><asp:Label ID="lblMeetingDate" runat="server" Font-Size="7pt" Text="Meeting Date:"></asp:Label></td></tr><tr><%--		                    <td colspan="1" align="center" style="width:15%;" valign="top"><asp:DropDownList ID="ddl_Agent" runat="server" Font-Size="8"></asp:DropDownList></td>--%><td colspan="1" align="center" valign="middle" style="width:36%;"><asp:DropDownList ID="ddl_Type" runat="server" Font-Size="8"></asp:DropDownList></td><td colspan="1" align="center" style="width:64%;"><table id="Table3" width="100%" border="1" style="text-align:center" cellpadding="0" cellspacing="0"><tr><td colspan="1" align="center" style="width:50%;"><%--<ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"></ajaxToolkit:ToolkitScriptManager>--%><asp:Label ID="lblAgent" runat="server" Font-Size="8pt" Text="From:"></asp:Label><asp:TextBox ID="tb_txt_Meeting_Date_From" ToolTip="Enter Date Only (no time value)" runat="server" Font-Size="8" Width="60px" maxlength="10"></asp:TextBox><%--<ajaxToolkit:CalendarExtender TargetControlID="tb_txt_Meeting_Date_From" ID="CalendarExtender2" runat="server"></ajaxToolkit:CalendarExtender>--%></td><td colspan="1" align="center" style="width:50%;"><asp:Label ID="Label1" runat="server" Font-Size="8pt" Text="To:"></asp:Label><asp:TextBox ID="tb_txt_Meeting_Date_To" ToolTip="Enter Date Only (no time value)" runat="server" Font-Size="8" Width="60px" maxlength="10"></asp:TextBox><%--<ajaxToolkit:CalendarExtender TargetControlID="tb_txt_Meeting_Date_To" ID="CalendarExtender1" runat="server"></ajaxToolkit:CalendarExtender>--%></td></tr></table></td></tr></table></td><td colspan="1" align="left" valign="middle" style="width:15%; padding-top:14px;"><asp:Button ID="btnApplyFilter" runat="server" Text="Apply Filter" onclick="Apply_Filter" Font-Size="8" /><asp:Button ID="btnClearFilter" runat="server" Text="Clear Filter" onclick="Clear_Filter" Font-Size="8" /></td><td valign="bottom" align="right" style="width:28%; color:black; font-weight:bold; font-size:7pt; margin-left:8px; "></td></tr></table></div></asp:Panel>

...
...
...

My web.config file contains:

<pages><controls><add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit"/></controls></pages>

Does anyone know why the AjaxControlToolKit is not working correctly?

CalendarExtender