void ResetInternal()
 {
     if (_property.IsSet)
     {
         _property.Reset();
         _designItem.NotifyPropertyChanged(this);
     }
 }
 void ResetInternal()
 {
     if (_property.IsSet)
     {
         var oldValue = _property.PropertyValue;
         _property.Reset();
         _designItem.NotifyPropertyChanged(this, oldValue, null);
     }
 }