Bug 336225 Trim bars do not get unrendered by the rendering engine when trimmed window is unrendered
The trim bars are "ignored" by the rendering engine as it does not perform an unrendering pass on them when the parent trimmed window is being unrendered.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/workbench/PartRenderingEngineTests.java
appContext.get(EModelService.class).removePerspectiveModel(
				perspectiveB, window);
		assertFalse(view.isDestroyed());
		assertNotNull(part.getContext().getParent());
		assertEquals(perspectiveA.getContext(), part.getContext().getParent());
	}
	public void testRemoveGuiBug324230() {
		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);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		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