HyperLink problem under Panel within UpdatePanel

The HyperLink under Panel within UpdatePanel is not clickable. When HyperLink is moved from sub panel to UpdatePanel, everything is good. Here is my code -

Page:

<asp:UpdatePanel ID="p开发者_如何学Python" runat="server" RenderMode="Inline" UpdateMode="Conditional">
 ...
 <some:UserControl ID="uc" runat="server" />
 ...
</asp:UpdatePanel>

SomeUserControl:

<asp:Panel ID="p" runat="server">
 ...
 <asp:HyperLink ID="hlExportFile" runat="server" />
 ...
</asp:Panel>

Would be glad to hear any solution. Thanks ahead!

---

You Panel needs an ID.