ASP Validation Group Not Working - asp.net

Question

There are several pages which show the same code, just different field names.
What I'm struggling to understand is why the validation is not getting called on button click which is set to cause validation, all fields, required field validators and regular expression validators all have the same group.
Update
I remember this working (a project that got dropped and then picked up) previously, so the only things I can think of is either the web.config or the c# back end stopping it. I would not have thought the back end of the page is doing this as the button causes validation on click.
What else could be stopping this?
Code:
<%# Page Title="" Language="C#" MasterPageFile="~/DirectDebit/MasterDDSite.Master" AutoEventWireup="true" CodeBehind="DDI_2.aspx.cs" Inherits="CustomerServicePortal.DDI_Forms.DDI_2" %>
<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
<script type="text/javascript">
function CheckNumeric(e) {
if (window.event) // IE
{
if ((e.keyCode < 48 || e.keyCode > 57) & e.keyCode != 8) {
event.returnValue = false;
return false;
}
}
else { // Fire Fox
if ((e.which < 48 || e.which > 57) & e.which != 8) {
e.preventDefault();
return false;
}
}
}
</script>
<style type="text/css">
.style1 {
height: 28px;
}
table {
border-spacing: 2px;
border-collapse: separate;
}
.valError {
color: red;
border: 2px solid red;
margin: 5px 0px;
padding: 15px;
}
.valError ul {
color: red;
}
.valError li {
color: red;
}
.validation_summary {
color: red !important;
}
</style>
<div class="jumboservice">
<h2>Company Details</h2>
<div id="cmpnyDetails">
<div class="ui-grid-a">
<div class="ui-block-a">
<h4>Title:</h4>
</div>
<div class="ui-block-b">
<span>
<asp:TextBox ID="title" runat="server" ValidationGroup="vg1"></asp:TextBox>
*</span>
<asp:RequiredFieldValidator ID="rfv1" runat="server" ControlToValidate="title" ValidationGroup="vg1" ErrorMessage="Title is a required field." Display="None"></asp:RequiredFieldValidator>
<asp:RegularExpressionValidator Display="None" ValidationGroup="vg1" ControlToValidate="title" ID="Rev3" ValidationExpression="^[\s\S]{2,5}$" runat="server" ErrorMessage="Title requires between 2 and 5 characters."></asp:RegularExpressionValidator>
</div>
</div>
<div class="ui-grid-a">
<div class="ui-block-a">
<h4>Forename(s):</h4>
</div>
<div class="ui-block-b">
<span>
<asp:TextBox ID="forename" runat="server" ValidationGroup="vg1"></asp:TextBox>
*</span>
<asp:RegularExpressionValidator Display="None" ValidationGroup="vg1" ControlToValidate="forename" ID="RegularExpressionValidator1" ValidationExpression="^[\s\S]{2,25}$" runat="server" ErrorMessage="Forename requires between 2 and 25 characters."></asp:RegularExpressionValidator>
<asp:RequiredFieldValidator ID="rfv2" runat="server" ControlToValidate="forename" ValidationGroup="vg1" ErrorMessage="Forename is a required field." Display="None"></asp:RequiredFieldValidator>
</div>
</div>
<div class="ui-grid-a">
<div class="ui-block-a">
<h4>Surname:</h4>
</div>
<div class="ui-block-b">
<span>
<asp:TextBox ID="surname" runat="server" ValidationGroup="vg1"></asp:TextBox>
*</span>
<asp:RequiredFieldValidator ID="rfv3" runat="server" ControlToValidate="surname" ValidationGroup="vg1" ErrorMessage="Surname is a required field." Display="None"></asp:RequiredFieldValidator>
<asp:RegularExpressionValidator Display="None" ValidationGroup="vg1" ControlToValidate="surname" ID="RegularExpressionValidator2" ValidationExpression="^[\s\S]{3,45}$" runat="server" ErrorMessage="Surname requires between 3 and 45 characters."></asp:RegularExpressionValidator>
</div>
</div>
<div class="ui-grid-a">
<div class="ui-block-a">
<h4>Telephone:</h4>
</div>
<div class="ui-block-b">
<span>
<asp:TextBox ID="CompanyTele" runat="server" onkeypress="CheckNumeric(event);" ValidationGroup="vg1"></asp:TextBox>
*</span>
<asp:RegularExpressionValidator Display="None" ValidationGroup="vg1" ControlToValidate="CompanyTele" ID="RegularExpressionValidator10" ValidationExpression="^[0-9]{10,20}$" runat="server" ErrorMessage="Telephone requires between 10 and 20 numbers."></asp:RegularExpressionValidator>
<asp:RequiredFieldValidator ID="rfv9" runat="server" ControlToValidate="CompanyTele" ValidationGroup="vg1" ErrorMessage="Telephone is a required field." Display="None"></asp:RequiredFieldValidator>
</div>
</div>
</div>
<p><strong>*</strong> - Fields marked with an asterisk are mandatory.</p>
<asp:ValidationSummary ID="ValidationSummary1"
runat="server" ShowMessageBox="false"
ShowSummary="true" ValidationGroup="vg1"
ForeColor="Red" DisplayMode="BulletList"
CssClass="valError" HeaderText="<span><strong>The below requires attention:</strong></span>" />
<div class="ui-grid-d">
<div class="ui-block-a">
<div data-role="main" class="ui-content">
<div data-role="controlgroup" data-type="horizontal">
<asp:Button ID="Submit" CausesValidation="true" ValidationGroup="vg1" runat="server" CssClass="ui-btn ui-corner-all" Text="continue" OnClick="Submit_Click" />
</div>
</div>
</div>
</div>
</div>
</asp:Content>

Answer 1

Remove the "validation group" from the text-box fields. You should only add the "validation group" in the validation field, referencing the control you wish to validate.