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.
bundles/org.eclipse.e4.ui.workbench.swt/src/org/eclipse/e4/ui/internal/workbench/swt/PartRenderingEngine.java
if (kid == element) {
				if (prevCtrl != null)
					elementCtrl.moveBelow(prevCtrl);
				else
					elementCtrl.moveAbove(null);
				return;
			} else if (kid.getWidget() instanceof Control) {
				prevCtrl = (Control) kid.getWidget();
			}
		}
	}
	/**
	 * Initialize a part renderer from the extension point.
	 * 
	 * @param context
	 *            the context for the part factories
	 */
	@PostConstruct
	void initialize(IEclipseContext context) {
		this.appContext = context;
		
		KeyFormatterFactory.setDefault(SWTKeySupport
				.getKeyFormatterForPlatform());
		
		context.set(IPresentationEngine.class.getName(), this);
		IRendererFactory factory = null;
		IContributionFactory contribFactory = context
				.get(IContributionFactory.class);
		try {
			factory = (IRendererFactory) contribFactory.create(factoryUrl,