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
partService.switchPerspective(perspectiveA);
		assertEquals(
				"partB is the only part in perspectiveA, thus, it should be the active part",
				partB, partService.getActivePart());
		partService.switchPerspective(perspectiveB);
		assertEquals(
				"partA should be the only part that's being shown in perspectiveB, thus, it should be the active part",
				partA, partService.getActivePart());
	}
	public void testHidePart_ActivationHistory17() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		window.getChildren().add(partA);
		window.setSelectedElement(partA);
		MPartStack partStack = BasicFactoryImpl.eINSTANCE.createPartStack();
		window.getChildren().add(partStack);
		MPart partB = BasicFactoryImpl.eINSTANCE.createPart();
		partB.setContributionURI("platform:/plugin/org.eclipse.e4.ui.tests/org.eclipse.e4.ui.tests.application.ClientEditor");
		partStack.getChildren().add(partB);
		MPart partC = BasicFactoryImpl.eINSTANCE.createPart();
		partStack.getChildren().add(partC);
		partStack.setSelectedElement(partC);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		assertNull(partB.getObject());
		EPartService partService = window.getContext().get(EPartService.class);