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
service.showPart(partB.getElementId(), PartState.ACTIVATE);
		assertEquals("Showing a part should alter the tab folder's selection",
				1, tabFolder.getSelectionIndex());
	}
	public void testPartStack_SetActiveChild3Bug299379() throws Exception {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		application.setContext(appContext);
		appContext.set(MApplication.class.getName(), application);
		MPartDescriptor descriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE
				.createPartDescriptor();
		descriptor
				.setContributionURI("platform:/plugin/org.eclipse.e4.ui.tests/org.eclipse.e4.ui.tests.workbench.SampleView");
		descriptor.setElementId("part");
		descriptor.setCategory("aStack");
		application.getDescriptors().add(descriptor);
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		MPartStack stack = BasicFactoryImpl.eINSTANCE.createPartStack();
		stack.getTags().add("aStack");
		window.getChildren().add(stack);
		wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		CTabFolder tabFolder = (CTabFolder) stack.getWidget();
		assertEquals(0, tabFolder.getItemCount());
		EPartService service = (EPartService) window.getContext().get(
				EPartService.class.getName());
		MPart shownPart = service.showPart("part", PartState.ACTIVATE);
		assertEquals(1, tabFolder.getItemCount());
		assertEquals(0, tabFolder.getSelectionIndex());