Bug 295611 [UI] The MPart tests leave many open shells
This turns out to be caused by the PRE's 'stop' method only working correctly when an MApplication is the 'uiRoot' element.
bundles/org.eclipse.e4.ui.workbench.swt/src/org/eclipse/e4/ui/workbench/swt/internal/PartRenderingEngine.java
Activator.trace(Policy.DEBUG_RENDERER, "Child Removed", null); 
				MUIElement removed = (MUIElement) event
						.getProperty(IUIEvents.EventTags.OldValue);
				
				
				if (!removed.isVisible())
					return;
				factory.hideChild(changedElement, removed);
			}
		}
	};
	private IEclipseContext appContext;
	protected Shell hackShell;
	protected MApplication theApp;
	public PartRenderingEngine() {
	}
	/**
	 * Initialize a part renderer from the extension point.
	 * 
	 * @param registry
	 *            the registry for the EP
	 * @param r
	 *            the created renderer
	 * @param context
	 *            the context for the part factories
	 * @param f
	 *            the IContributionFactory already provided to <code>r</code>
	 */
	@PostConstruct
	private void initialize(IEclipseContext context) {