Bug 299438 [CommonNavigator] CNF viewer state non properly reset when NCEs are activated or deactivated
The map of the objects to the NCEs should be reset whenever the NCEs associated with the viewer to change to avoid having stale label information. This has shown up when looking at the CNF tests that change the viewer.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
IMementoAware, INavigatorContentService {
	/**
	 * 
	 */
	public static final String WIDGET_KEY = "org.eclipse.ui.navigator"; 
	
	private static final NavigatorContentDescriptorManager CONTENT_DESCRIPTOR_REGISTRY = NavigatorContentDescriptorManager
			.getInstance();
	private static final NavigatorViewerDescriptorManager VIEWER_DESCRIPTOR_REGISTRY = NavigatorViewerDescriptorManager
			.getInstance();
	private static final ITreeContentProvider[] NO_CONTENT_PROVIDERS = new ITreeContentProvider[0];
	private static final ILabelProvider[] NO_LABEL_PROVIDERS = new ILabelProvider[0];
	private static final INavigatorContentDescriptor[] NO_DESCRIPTORS = new INavigatorContentDescriptor[0];
	private static final String[] NO_EXTENSION_IDS = new String[0];
	private final NavigatorViewerDescriptor viewerDescriptor;
	private final List listeners = new ArrayList();
	/*
	 * A map of (String-based-Navigator-Content-Extension-IDs,
	 * NavigatorContentExtension-objects)-pairs
	 */
	private final Map contentExtensions = new HashMap();
	private StructuredViewerManager structuredViewerManager;