Bug 329482 Uninstantiated part may be rendered when closing another part in the same stack
1. Activate the 'Javadoc' view. 2. Activate the 'Package Explorer' view. 3. Shutdown. 4. Restart. 5. Ctrl+3 > Properties 6. Hide the 'Properties' view. 7. Now the 'Problems' view is the selected element. It should be the 'Javadoc' view.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
windowService1.activate(part);
		assertEquals("The part should have been activated", part,
				windowService1.getActivePart());
		assertNull("The second window has no parts, this should be null",
				windowService2.getActivePart());
		
		window2.getChildren().add(part);
		
		windowService2.activate(part);
		assertEquals("No parts in this window, this should be null", null,
				windowService1.getActivePart());
		assertEquals("We activated it just now, this should be active", part,
				windowService2.getActivePart());
	}
	public void testApplicationContextHasActivePart() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		MPart partB = BasicFactoryImpl.eINSTANCE.createPart();
		window.getChildren().add(partA);
		window.getChildren().add(partB);
		window.setSelectedElement(partA);
		
		initialize(applicationContext, application);
		
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(