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
if (parentME != null) {
			AbstractPartRenderer factory = getFactoryFor(parentME);
			if (factory != null) {
				parent = factory.getUIContainer(element);
			}
		}
		return createGui(element, parent);
	}
	/**
	 * @param element
	 */
	public void removeGui(MUIElement element) {
		AbstractPartRenderer factory = getFactoryFor(element);
		assert (factory != null);
		MUIElement parent = element.getParent();
		AbstractPartRenderer parentFactory = parent != null ? getFactoryFor(parent)
				: null;
		if (parentFactory != null) {
			parentFactory.hideChild(element.getParent(), element);
		}
		if (factory != null)
			factory.disposeWidget(element);
		else
			System.out.println("Null factory in removeGui");
		
		if (element instanceof MContext) {
			MContext ctxt = (MContext) element;
			IEclipseContext lclContext = ctxt.getContext();
			ctxt.setContext(null);
			if (lclContext instanceof IDisposable) {