Bug 327933 Unrendering container with invalid selectedElement can cause target element to be unrendered
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/workbench/PartRenderingEngineTests.java
wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		CTabFolder tabFolder = (CTabFolder) stack.getWidget();
		assertEquals(0, tabFolder.getSelectionIndex());
		EPartService service = (EPartService) window.getContext().get(
				EPartService.class.getName());
		service.activate(partB);
		assertEquals(1, tabFolder.getSelectionIndex());
		service.activate(partA);
		partA.setToBeRendered(false);
		assertEquals(1, tabFolder.getItemCount());
		assertEquals(0, tabFolder.getSelectionIndex());
		assertEquals(partB, stack.getSelectedElement());
	}
	public void testCreateGuiBug301950() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		final MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setContext(appContext);
		appContext.set(MApplication.class.getName(), application);
		wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		part.setContributionURI("platform:/plugin/org.eclipse.e4.ui.tests/org.eclipse.e4.ui.tests.workbench.SampleView");
		window.getChildren().add(part);
		IPresentationEngine renderer = (IPresentationEngine) appContext
				.get(IPresentationEngine.class.getName());
		renderer.createGui(part);
		renderer.removeGui(part);