Bug 329310 Part service does not autogenerate stacks if the last container is not one
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		window.getSharedElements().add(part);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE
				.createPerspectiveStack();
		window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);
		MPerspective perspective = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspective);
		perspectiveStack.setSelectedElement(perspective);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EModelService modelService = window.getContext().get(
				EModelService.class);
		EPartService partService = window.getContext().get(EPartService.class);
		MPlaceholder placeholder = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		placeholder.setRef(part);
		part.setCurSharedRef(placeholder);
		partService.showPart(part, PartState.ACTIVATE);
		List<MPart> parts = modelService.findElements(perspective,
				part.getElementId(), MPart.class, null);
		assertEquals(1, parts.size());
		assertEquals(part, parts.get(0));
		List<MPlaceholder> placeholders = modelService.findElements(