Bug 280846 [UI][CSS] Null styling engine required in main context for tests to run
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/workbench/ui/internal/Workbench.java
for (MPart<?> child : children) {
			processHandlers((MPart<MPart<?>>) child);
		}
	}
	/**
	 * 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>
	 */
	public static void initializeRenderer(IExtensionRegistry registry, PartRenderer r,
			IEclipseContext context, IContributionFactory f) {
		
		
		
		IConfigurationElement[] factories = registry
				.getConfigurationElementsFor("org.eclipse.e4.workbench.partfactory"); 
		
		
		int offset = 0;
		for (int i = 0; i < factories.length; i++) {
			String clsSpec = factories[i].getAttribute("class"); 
			if (clsSpec.indexOf("Legacy") >= 0 
					|| clsSpec.indexOf("PartSash") >= 0) {