private void ClearViewport()
        {
            foreach (var diagramConnectorViewModel in DiagramConnectorViewModels.ToArray())
            {
                RemoveFromViewModels(diagramConnectorViewModel);
            }

            foreach (var diagramNodeViewModel in DiagramNodeViewModels.ToArray())
            {
                RemoveFromViewModels(diagramNodeViewModel);
            }

            _diagramShapeToViewModelMap.Clear();
        }
        private void ClearViewport()
        {
            foreach (var diagramConnectorViewModel in DiagramConnectorViewModels.ToArray())
            {
                RemoveConnector(diagramConnectorViewModel.DiagramConnector);
            }

            foreach (var diagramNodeViewModel in DiagramNodeViewModels.ToArray())
            {
                RemoveNode(diagramNodeViewModel.DiagramNode);
            }

            _diagramConnectorToViewModelMap.Clear();
            _diagramNodeToViewModelMap.Clear();
        }