public override void Dispose()
        {
            base.Dispose();

            ViewportCalculator.TransformChanged -= OnViewportTransformChanged;
            DiagramService.DiagramChanged       -= OnDiagramChanged;

            ViewportCalculator.Dispose();
            MiniButtonPanelViewModel.Dispose();

            foreach (var diagramNodeViewModel in DiagramNodeViewModels)
            {
                diagramNodeViewModel.Dispose();
            }

            foreach (var diagramConnectorViewModel in DiagramConnectorViewModels)
            {
                diagramConnectorViewModel.Dispose();
            }
        }
        public void Dispose()
        {
            UnsubscribeFromViewportEvents();
            UnsubscribeFromDiagramEvents();
            UnsubscribeFromDiagramShapeButtonEvents();

            ViewportCalculator.Dispose();

            foreach (var diagramNodeViewModel in DiagramNodeViewModels)
            {
                diagramNodeViewModel.Dispose();
            }

            foreach (var diagramConnectorViewModel in DiagramConnectorViewModels)
            {
                diagramConnectorViewModel.Dispose();
            }

            foreach (var diagramShapeButtonViewModel in DiagramNodeButtonViewModels)
            {
                diagramShapeButtonViewModel.Dispose();
            }
        }