Bug 334644 Cannot manually un/render a window that's directly under the application
Setting the 'toBeRendered' flag for a window that's a direct child of an application does nothing. The workaround is to manually de/construct it via the IPresentationEngine.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/workbench/PartRenderingEngineTests.java
part.setToBeRendered(false);
		
		sashContainer.getChildren().add(part);
		application.setContext(appContext);
		appContext.set(MApplication.class.getName(), application);
		wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		assertNotNull(sashContainer.getWidget());
		appContext.get(IPresentationEngine.class).removeGui(sashContainer);
		assertNull(sashContainer.getWidget());
	}
	public void testBug317849() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPartSashContainer sashContainer = BasicFactoryImpl.eINSTANCE
				.createPartSashContainer();
		window.getChildren().add(sashContainer);
		window.setSelectedElement(sashContainer);
		MPlaceholder sharedAreaPlaceholder = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		sashContainer.getChildren().add(sharedAreaPlaceholder);
		sashContainer.setSelectedElement(sharedAreaPlaceholder);
		MPartSashContainer sharedSashContainer = BasicFactoryImpl.eINSTANCE
				.createPartSashContainer();
		sharedAreaPlaceholder.setRef(sharedSashContainer);
		sharedSashContainer.setCurSharedRef(sharedAreaPlaceholder);
		MPartStack partStack = BasicFactoryImpl.eINSTANCE.createPartStack();