public static void setRootGraph(Diagram diagram, Graph graph) {

		PictogramLink link = diagram.getLink();

		if (link == null) {

			// Create the pictogram link object
			link = PictogramsFactory.eINSTANCE.createPictogramLink();
		}

		EditingDomain editingDomain = AdapterFactoryEditingDomain.getEditingDomainFor(diagram);
		Command command;

		// Remove the Graph from the diagram resource
		command = new RemoveCommand(editingDomain, diagram.eResource().getContents(), link.getBusinessObjects());
		editingDomain.getCommandStack().execute(command);

		// Add the Graph to the diagram resource
		link.getBusinessObjects().clear();
		link.getBusinessObjects().add(graph);

		command = new AddCommand(editingDomain, diagram.eResource().getContents(), graph);
		editingDomain.getCommandStack().execute(command);

		// Set the pictogram link object for the diagram object
		command = new SetCommand(editingDomain, diagram,
				PictogramsPackage.eINSTANCE.getDiagram().getEStructuralFeature(PictogramsPackage.DIAGRAM__LINK), link);
		editingDomain.getCommandStack().execute(command);
	}

	@Override
	public void execute(ICustomContext context) {

		hasDoneChanges = true;

		// Access the graph
		Graph theGraph = GraphUtil.getRootGraph(getDiagram());

		// Add every node from the new graph
		theGraph.getNodes().clear();
		theGraph.getNodes().addAll(newGraph.getNodes());

		// Add every edge from the new graph
		theGraph.getEdges().clear();
		theGraph.getEdges().addAll(newGraph.getEdges());

		// Model is modified now, with new or different edges
		updateAllEdges();
		updateGraph(theGraph);

	}

			Node node = theGraph.getNodes().get(i);
			PictogramElement pictogramElement = Graphiti.getLinkService().getPictogramElements(diagram, node)
					.get(0);
			DeleteContext delContext = new DeleteContext(pictogramElement);
			delContext.setMultiDeleteInfo(new MultiDeleteInfo(false, false, 0));
			getFeatureProvider().getDeleteFeature(delContext).execute(delContext);

			Node node = newGraph.getNodes().get(i);
			theGraph.getNodes().add(node);
			AddContext addContext = new AddContext();
			addContext.setNewObject(node);
			addContext.setLocation(node.getXCoord(), node.getYCoord());
			addContext.setTargetContainer(diagram);
			getFeatureProvider().getAddFeature(addContext).add(addContext);