Tab headers of Tab Container within the Update Panel

I have a TabContainer inside of Update Panel. It seems that the background style of the tab header don't shows.

<asp:Button ID="Button1" runat="server" Text="View Tab" />

<asp:UpdatePanel ID="UpdatePanel4" runat="server">
<ContentTemplate>

<table id="Table1" runat="server">
<tr>
<td>
<ajaxToolkit:TabContainer ID="TabContainer1" runat="server">
 <ajaxToolkit:TabPanel ID="TabPanel1" HeaderText="Tab 1" runat="server">
 <ContentTemplate>
Text 1
 </ContentTemplate>
 </ajaxToolkit:TabPanel>
 <ajaxToolkit:TabPanel ID="TabPanel1" HeaderText="Tab 2" runat="server">
 <ContentTemplate>
Text 2
 </ContentTemplate>
 </ajaxToolkit:TabPanel>
</ajaxToolkit:TabContainer>
</td>
</tr>
</table>
</ContentTemplate>
</asp:UpdatePanel>

Is there any other ways to bring back the background style of the tab header.

Thanks in advance

Please help me on this...

You can add a CSS class to your TabContainer. The toolkit ships with the style ajax__tab_xp to ensure its loaded see below.

<Ajax:TabContainerID="TabContainer1"runat="server"CssClass="ajax__tab_xp">

If you still experince issues use fiddler www.fiddlertool.com to check that the XP style sheet is sent as a web resource.