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
if (navigatorActivationService == null) {
			navigatorActivationService = new NavigatorActivationService(this);
		}
		return navigatorActivationService;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.ui.navigator.INavigatorContentService#getSaveableService()
	 */
	public INavigatorSaveablesService getSaveablesService() {
		synchronized (this) {
			if (navigatorSaveablesService == null) {
				navigatorSaveablesService = new NavigatorSaveablesService(this);
				assistant.addListener(navigatorSaveablesService);
			}
			return navigatorSaveablesService;
		}
	}
	/**
	 * Not API as of 3.3.
	 * 
	 * @return The extension state service for this content service.
	 * 
	 */
	public NavigatorExtensionStateService getExtensionStateService() {
		if (navigatorExtensionStateService == null) {
			navigatorExtensionStateService = new NavigatorExtensionStateService(
					this);