private void FollowedObject_NotifyPropertyChanging(object sender, NotificationArg arg)
 {
     // if the object was not disposed and someone "listen" about this event we wont to rise it
     if (!((INotify)sender).Disposed && ((INotify)sender).SuspendListener == false)
     {
         this.AddToUndo(new ObjectPropertyValuePair(ref sender, arg.PropertyKey, arg.OldValue));
     }
 }
 private void FollowedObject_NotifyPropertyChanging(object sender, NotificationArg arg)
 {
     // if the object was not disposed and someone "listen" about this event we wont to rise it
     if(!((INotify)sender).Disposed  && ((INotify)sender).SuspendListener == false )
         this.AddToUndo(new ObjectPropertyValuePair(ref sender, arg.PropertyKey, arg.OldValue));
 }