Created Issue: TabContainer render duplicated component bug [27365]

I find that Ajax 4.0 renders header label incorrectly in Ajax Tab Container. After some checking, I find it renders the header twice if there is a component in header template. How can I solve the problem?

```
<act:TabContainer ID="tcControl" runat="server" ActiveTabIndex="0" AutoPostBack="false">
<act:TabPanel ID="tpSearch" runat="server">
<HeaderTemplate>
<asp:LinkButton ID="TabContainerHeaderSearch" runat="server" Width="150" Text="Search" OnClick="TabContainerHeader_Click" />
</HeaderTemplate>
<ContentTemplate>
<asp:Panel ID="plSearch" runat="server">
Test
</asp:Panel>
</ContentTemplate>
</act:TabPanel>
</act:TabContainer>
```