ValidateItem is always false

[CD]

I am copying the example here:
http://demos.telerik.com/silverlight/#DataForm/DataFormRIA

I am using the Northwind database and WCF RIA services.



Whenever I save an edit,  I check MyRadDataForm.ValidateItem()  and it is always false. If I ignore that and call

MyRadDomainDataSource.SubmitChanges() the edit is saved.

private void MyRadDataForm_EditEnding(object sender, Telerik.Windows.Controls.Data.DataForm.EditEndingEventArgs e)
{
    if (MyRadDataForm.ValidateItem())// Why False??
    {
        MyRadDomainDataSource.SubmitChanges();
    }
    else
    {
        System.Diagnostics.Debug.WriteLine("Invalid Item");
    }
}