Bug 326175 WBWRenderer arbitrarily modifies the window's parent's active context chain
The window's parent's context arbitrarily changes its active child to the window being rendered in createWidget(*).
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/workbench/PartRenderingEngineTests.java
wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		assertNotNull(detachedWindow.getContext());
		assertNotNull(detachedWindow.getWidget());
		perspective.setToBeRendered(false);
		assertNull(detachedWindow.getContext());
		assertNull(detachedWindow.getWidget());
	}
	public void testRemoveGui_Bug334577_02() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MWindow detachedWindow = BasicFactoryImpl.eINSTANCE.createWindow();
		window.getWindows().add(detachedWindow);
		application.setContext(appContext);
		appContext.set(MApplication.class.getName(), application);
		wb = new E4Workbench(application, appContext);
		wb.createAndRunUI(window);
		assertNotNull(detachedWindow.getContext());
		assertNotNull(detachedWindow.getWidget());
		window.setToBeRendered(false);
		assertNull(detachedWindow.getContext());
		assertNull(detachedWindow.getWidget());
	}
	/**
	 * Test to ensure that we don't get an exception while rendering a child of
	 * an MTrimBar that doesn't have its element id set.
	 */