Validation summary not showing in content page

I have a simple content page:<%@ Page Language="VB" MasterPageFile="~/Master1.master" AutoEventWireup="false" CodeFile="Login.aspx.vb" Inherits="Login" title="Untitled Page" %><asp:Content ID="Content1" ContentPlaceHolderID="MasterContent" Runat="Server">    <asp:Login ID="Login1" runat="server">    </asp:Login>    <asp:ValidationSummary ID="ValidationSummary1" runat="server"         ValidationGroup="Login1" /></asp:Content> But the validation summary is not appearing when a password is not entered. I think it may have something to do with being a content page because when I put the same code into a normal webform page the validation summary works fine. There is a blank space on the page for the validation summary, and the login control displays the red asterisk indicating an error. But the err ...