title: TabContainer from AJAX Toolkit not visible in browser (including ToolkitScriptManager)
body: <p>Hi I have Visual Studio Express 2012 for Web
  I installed AJAX Control Toolkit .NET 4.5 from <a href="http://ajaxcontroltoolkit.codeplex.com/releases/view/109918" rel="nofollow">http://ajaxcontroltoolkit.codeplex.com/releases/view/109918</a></p>
  
  <p>I added AjaxControlToolkit.dll to project resources, then I added it to ToolBox -> Choose items.</p>
  
  <p>Everything works find in design mode, I can see the TabControl, but when I compile to a website, the control is not visible.</p>
  
  <p>Visual Studio Code:</p>
  
  <pre><code>&lt;%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="JuwentWebASP_kurtyny.WebForm1" %&gt;
  
  &lt;%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="asp" %&gt;
  
  &lt;!DOCTYPE html&gt;
  
  &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
  &lt;head runat="server"&gt;
      &lt;title&gt;&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;form id="form1" runat="server"&gt;
      &lt;div&gt;
  
          &lt;asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"&gt;
          &lt;/asp:ToolkitScriptManager&gt;
          &lt;br /&gt;
          &lt;asp:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="0" Width="479px"&gt;
              &lt;asp:TabPanel runat="server" HeaderText="TabPanel1" ID="TabPanel1"&gt;
                  &lt;ContentTemplate&gt;
                      sdfsdfsfsdf
                  &lt;/ContentTemplate&gt;
              &lt;/asp:TabPanel&gt;
              &lt;asp:TabPanel ID="TabPanel2" runat="server" HeaderText="TabPanel2"&gt;
                  &lt;ContentTemplate&gt;
                      sdfdfsdfsdf
                  &lt;/ContentTemplate&gt;
              &lt;/asp:TabPanel&gt;
          &lt;/asp:TabContainer&gt;
  
      &lt;/div&gt;
      &lt;/form&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>Website source:
  <a href="http://pastebin.com/YJSmAY1N" rel="nofollow">http://pastebin.com/YJSmAY1N</a></p>