private static void IncludeVolumesOnOFFLayersPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            NeighborhoodGraph instance = d as NeighborhoodGraph;

            if (instance == null)
            {
                return;
            }

            instance.ExtractVolumesToSort();
        }
        private static void VolumeManagerContentChangePropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            NeighborhoodGraph instance = d as NeighborhoodGraph;

            if (instance == null)
            {
                return;
            }

            // exract volumes to sort
            instance.ExtractVolumesToSort();
        }
        private static void VolumeManagerPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            NeighborhoodGraph instance = d as NeighborhoodGraph;

            if (instance == null || instance.VolumeManager == null)
            {
                instance.volumes_tested = new Dictionary <ZonedVolume, bool>();
                return;
            }

            // exract volumes to sort
            instance.ExtractVolumesToSort();
        }