Asp.Net tab control not visible - asp.net

Question

Problem is simple the tab control shows in design mode but is not getting shown when viewing from browser. Enable and Visible is true. Although the controls are getting rendered and I can see the HTML.
I am using .NET 3.5 AND TOOLKIT version is 3.5.4xxxx
Page code is like this. Right now ther is nothing in the code behind.
<%# Page Language="C#" AutoEventWireup="true" MasterPageFile="~/MasterPage.Master" CodeFile="OrderDetailsPage.aspx.cs" Inherits="OrderDetailsPage" Title="Order Page" EnableViewState="true" %>
<%# Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</asp:ToolkitScriptManager>
<div id="pagetitle">
<asp:Literal ID="caseHeader" runat="server">Loyalty Management Partner Portal</asp:Literal>
</div>
<!--CONTENT CONTAINER-->
<div id="content-container-two-column">
<!--CONTENT SIDE 1 COLUMN-->
<div id="content-side-two-column" height="780px">
<ul class="list-of-links">
<li>Loyalty Management</li>
<li>Orders Status Page</li>
</ul>
<br />
</div>
<!--CENTER COLUMN-->
<div id="content-main-two-column">
<strong class="headerText">Order Details Page</strong>
<br />
<br />
<h3 class="helpText">
Provide details of Order. You can update order status, Add notes to orders.
</h3>
<asp:Label ID="lblError" CssClass="error" ForeColor="Red" runat="server" />
<hr />
<asp:TabContainer ID="tabContainer1" runat="server" Width="100%" Height="250px">
<asp:TabPanel runat="server" ID="tabOrder" HeaderText="Order">
<ContentTemplate>
<table width="100%">
<tr>
<td valign="top" width="15%">
<b>Order No.</b>
</td>
<td width="85%" colspan="4" valign="top">
<asp:Label ID="lblOrderNo" runat="server"></asp:Label>
</td>
</tr>
<tr>
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel ID="tabOrderDetails" runat="server" HeaderText="Ordered Items">
<ContentTemplate>
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel ID="tabNotes" runat="server" HeaderText="Notes">
<ContentTemplate>
<table width="100%">
<tr>
<td></td>
<td></td>
</tr>
</table>
</ContentTemplate>
</asp:TabPanel>
</asp:TabContainer>
</div>
<div class="clear">
</div>
</div>
</asp:Content>

Answer 1

I uninstalled the Ajax toolkit and reinstall it to make it working.