Bug 185181 [CommonNavigator] NPE from Customize View of Project Explorer
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorPlugin.java
private BundleListener bundleListener = new BundleListener() {
		public void bundleChanged(BundleEvent event) {
			NavigatorSaveablesService.bundleChanged(event);
		}
	};
	/**
	 * Creates a new instance of the receiver
	 */
	public NavigatorPlugin() {
		super();
		plugin = this;
	}
	/**
	 * @return the shared instance.
	 */
	public static NavigatorPlugin getDefault() {
		return plugin;
	}
	/**
	 * Returns an image descriptor for the image file at the given plug-in
	 * relative path.
	 * 
	 * @param path
	 *            the path
	 * @return the image descriptor
	 */
	public static ImageDescriptor getImageDescriptor(String path) {
		return AbstractUIPlugin.imageDescriptorFromPlugin(PLUGIN_ID, path);
	}