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
assertNull(part.getRenderer());
		assertNull(part.getObject());
		assertEquals(0, tabFolder.getItemCount());
	}
	public void testCTabItem_SetControl_Bug304211() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		application.setContext(appContext);
		appContext.set(MApplication.class.getName(), application);
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		MPartStack stack = BasicFactoryImpl.eINSTANCE.createPartStack();
		window.getChildren().add(stack);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		partA.setElementId("partA");
		partA.setContributionURI("platform:/plugin/org.eclipse.e4.ui.tests/org.eclipse.e4.ui.tests.workbench.SampleView");
		stack.getChildren().add(partA);
		stack.setSelectedElement(partA);
		wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		IPresentationEngine engine = (IPresentationEngine) appContext
				.get(IPresentationEngine.class.getName());
		CTabFolder folder = (CTabFolder) stack.getWidget();
		CTabItem itemA = folder.getItem(0);
		assertEquals(
				"The presentation engine should have created the part and set it",
				partA.getWidget(), itemA.getControl());
		MPart partB = BasicFactoryImpl.eINSTANCE.createPart();
		partB.setElementId("partB");
		partB.setContributionURI("platform:/plugin/org.eclipse.e4.ui.tests/org.eclipse.e4.ui.tests.workbench.SampleView");