Bug 318713 Duplicate toolbar items (navigate group)
SDK 4.0 - I20100701-1105. 1. start fresh workspace ==> navigate group appears twice which is quite confusing and wastes space.
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/TrimBarRenderer.java
*
 */
public class TrimBarRenderer extends SWTPartRenderer {
	private MApplication application;
	private HashMap<MTrimBar, ArrayList<ArrayList<MTrimElement>>> pendingCleanup = new HashMap<MTrimBar, ArrayList<ArrayList<MTrimElement>>>();
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer#init(org.eclipse
	 * .e4.core.contexts.IEclipseContext)
	 */
	@Override
	public void init(IEclipseContext context) {
		super.init(context);
		application = context.get(MApplication.class);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.renderers.PartFactory#createWidget(org.eclipse
	 * .e4.ui.model.application.MPart)
	 */
	@Override
	public Object createWidget(MUIElement element, Object parent) {
		if (!(element instanceof MTrimBar) || !(parent instanceof Composite))
			return null;
		Composite parentComp = (Composite) parent;
		if (!(parentComp.getLayout() instanceof TrimmedPartLayout))