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.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
* Might be null if this part service is created for the application
	 */
	private MWindow workbenchWindow;
	@Inject
	private IPresentationEngine engine;
	@Inject
	private EModelService modelService;
	@Inject
	private Logger logger;
	@Inject
	@Optional
	private ISaveHandler saveHandler;
	@Inject
	private IEventBroker eventBroker;
	private PartActivationHistory partActivationHistory;
	private MPart activePart;
	private MPart lastActivePart;
	private ListenerList listeners = new ListenerList();
	private boolean constructed = false;
	@Inject
	public PartServiceImpl(MApplication application, @Optional MWindow window) {
		
		this.application = application;
		workbenchWindow = window;
	}
	@Inject
	void setPart(@Optional @Named(IServiceConstants.ACTIVE_PART) MPart p) {
		if (activePart != p) {
			lastActivePart = activePart;
			activePart = p;