<com:TContent ID="Content"> Global state: <com:TTextBox ID="TextBox2" /> <com:TButton Text="Submit" OnClick="updateGlobal" /> <br/> Your input: <com:TTextBox ID="TextBox" /> <com:TButton Text="Submit" ValidationGroup="Foo" OnClick="buttonClicked" /> <com:TCustomValidator ValidationGroup="Foo" ControlToValidate="TextBox" Text="Your input must match the global state." OnServerValidate="customValidation" /> <br/> </com:TContent>