UpdatePanel Slowness in IE

function showAttendMenu(callingControl, guid) {
var myPnl = $get('" + this.MyPnl.ClientID + @"')
if(myPnl) {
	var displayIDFld = $get('" + this.AttendanceFld.ClientID + @"');
	var myStyle = myPnl.style;
	if(myStyle.display == 'block' && (guid== '' || guid == displayIDFld.value)) {
		myStyle.display = 'none';
	} else {
		// Get a reference to the PageRequestManager.
		var prm = Sys.WebForms.PageRequestManager.getInstance();

		// Unblock the form when a partial postback ends.
		prm.add_endRequest(function() {
			$('#" + this.MyPnl.ClientID + @"').unblock({ fadeOut: 0});
		});

		var domEl = Sys.UI.DomElement;
		//Move it into position
		var loc = domEl.getLocation(callingControl);
		var width = domEl.getBounds(callingControl).width;
		domEl.setLocation(myPnl, loc.x + width, loc.y - 200);

		//Show it and block it until we finish loading the data
		myStyle.display = 'block';
		$('#" + this.MyPnl.ClientID + @"').block({ message: null, overlayCSS: { backgroundColor:'#fff', opacity: '0.7'} });

		//Load the data
		if(guid != '') { displayIDFld.value = guid; }
		__doPostBack('" + UpdatePanel1.ClientID + @"','');
	}
}}

// In your aspx.cs define the server-side method marked with the
// WebMethod attribute and it must be public static.
[WebMethod]
public static string HelloWorld(string name)
{
  return "Hello World - by " + name;
}

// Call the method via javascript
PageMethods.HelloWorld("Jimmy", callbackMethod, failMethod);

<script type="text/javascript" src="<%=Response.ApplyAppPathModifier("~/js/jquery-1.2.6.js") %>"></script>
<script type="text/javascript" src="<%=Response.ApplyAppPathModifier("~/js/jquery.blockUI.js") %>"></script>
<asp:Panel CssClass="PopOutBox noPrint" ID="MyPnl" style="display: none; z-index:1000; width:230px; position: absolute;" runat="server">
    <cmp:Image MyImageType="SmallCancel" CssClass="fright" runat="server" ID="CloseImg" AlternateText="Close" />
    <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">

    	<ContentTemplate>
    		<asp:HiddenField ID="AttendanceFld" runat="server"  />
    		<asp:HiddenField ID="DatePickerFld" runat="server"  />
    		<table width="100%">
    			<tr>
    				<td valign="top">
    					<asp:RadioButtonList EnableViewState="false" ID="AttendRBL" runat="server" RepeatDirection="Vertical">
    						<asp:ListItem Selected="True" Text="On Time" Value="" />
    						<asp:ListItem Text="Late" Value="Late" />
    						<asp:ListItem Text="Absent" Value="Absent" />
    						<asp:ListItem Text="Cleaning Flunk" Value="Other" title="This is used for things like cubby flunks" />
    						<asp:ListItem Text="Major Cleaning Flunk" Value="Major" title="This is used for things like White Glove flunks" />
    					</asp:RadioButtonList>
    				</td>
    				<td valign="top" style="text-align: center; vertical-align: middle;">
    					<asp:CheckBox EnableViewState="false" ID="ExcusedCB" runat="server" />
    					<br />
    					<asp:Label ID="Label1" EnableViewState="false" AssociatedControlID="ExcusedCB" Text="Excused"
    						runat="server" />
    				</td>
    			</tr>

    			<tr>
    				<td colspan="2">
    					<asp:Label EnableViewState="false" ID="Label2" Text="Notes" runat="server" AssociatedControlID="DataTB" />
    					<cmp:HelpPopUp EnableViewState="false" runat="server" Text='Must include "Out Sick" to be counted as ill on reports and progress reports' />
    					<br />
    					<asp:TextBox ID="DataTB" EnableViewState="false" runat="server" Columns="30" /><br />
    					<div style="font-size: 10px; text-align:center;">
    						<a href="#" onclick="setAttendVal('<%=this.DataTB.ClientID%>','Out Sick');return false;">
    							(Ill)</a> <a href="#" onclick="setAttendVal('<%=this.DataTB.ClientID%>','In Ethics');return false;">
    								(Ethics)</a> <a href="#" onclick="setAttendVal('<%=this.DataTB.ClientID %>','Warned');return false;">
    									(Warned)</a>
    					</div>
    				</td>
    			</tr>
    			<tr>
    				<td colspan="2">
    					<cmp:ImageButton ID="DeleteBtn" OnClientClick="showAttendMenu(this,'');" OnClick="DeleteAttendance" ButtonType="SmallDelete"
    						CssClass="fright" runat="server" />
    					<cmp:ImageButton ID="SaveBtn" OnClientClick="showAttendMenu(this,'');" OnClick="SaveAttendance" ButtonType="SmallSave" runat="server" />
    				</td>
    			</tr>
    		</table>
    	</ContentTemplate>
    </asp:UpdatePanel>
</asp:Panel>