private void OnFieldValueChanged(object sender, ValueChangedEventArgs e)
        {
            _log.Debug(m => m("EditViewModel.OnFieldValueChanged invoked; value changed from '{0}' to '{1}'", e.OldValue, e.NewValue));

            bool previousState = _underlyingEdit.CurrentState;

            _underlyingEdit.Evaluate(FixFieldValueProvider.Empty);

            NotifyStateChange(e.Id, previousState, _underlyingEdit.CurrentState);
        }