Editor dissapears on partial postback...

Hello,

I have a page that shows a ckeditor in an udate panel. My page is as follows:

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
	<title></title>
</head>

<body>
	<form id="form1" runat="server">
		<cc1:ToolkitScriptManager runat="server" ID="ToolkitScriptManager" EnablePartialRendering="true"></cc1:ToolkitScriptManager>
		<div>
			<asp:Label ID="Label1" runat="server" Text="Hello"></asp:Label><br />
			<br />
			<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
				<ContentTemplate>
					<script src="../../../../../ckeditor/ckeditor.js" type="text/javascript"></script>

					<asp:TextBox class="ckeditor" ID="tbEditorHeader" runat="server" ClientIDMode="Static" TextMode="MultiLine" Columns="80" Rows="4"></asp:TextBox>

					<asp:Button ID="Button1" runat="server" Text="Button" />
				</ContentTemplate>
			</asp:UpdatePanel>
		</div>
	</form>
</body>
</html>

Has anyone seen this issue? Any known solutions?

Thanks for the help!!