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
if (object != null && requiresFocus) {
			ContextInjectionFactory.invoke(object, Focus.class, part.getContext(), null);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.e4.ui.workbench.modeling.EPartService#getActivePart()
	 */
	public MPart getActivePart() {
		return activePart;
	}
	private MPartDescriptor findDescriptor(String id) {
		for (MPartDescriptor descriptor : application.getDescriptors()) {
			if (descriptor.getElementId().equals(id)) {
				return descriptor;
			}
		}
		return null;
	}
	private MPart createPart(MPartDescriptor descriptor) {
		if (descriptor == null) {
			return null;
		}
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		part.setElementId(descriptor.getElementId());
		part.getMenus().addAll(EcoreUtil.copyAll(descriptor.getMenus()));
		if (descriptor.getToolbar() != null) {
			part.setToolbar((MToolBar) EcoreUtil.copy((EObject) descriptor.getToolbar()));
		}