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 (result.isEmpty()) {
			return NO_DESCRIPTORS;
		}
		return (INavigatorContentDescriptor[]) result
				.toArray(new INavigatorContentDescriptor[result.size()]);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.ui.navigator.INavigatorContentService#bindExtensions(java
	 * .lang.String[], boolean)
	 */
	public INavigatorContentDescriptor[] bindExtensions(String[] extensionIds,
			boolean isRoot) {
		if (extensionIds == null || extensionIds.length == 0) {
			return NO_DESCRIPTORS;
		}
		for (int i = 0; i < extensionIds.length; i++) {
			assistant.bindExtensions(extensionIds, isRoot);
		}
		Set boundDescriptors = new HashSet();
		INavigatorContentDescriptor descriptor;
		for (int i = 0; i < extensionIds.length; i++) {
			descriptor = CONTENT_DESCRIPTOR_REGISTRY
					.getContentDescriptor(extensionIds[i]);
			if (descriptor != null) {
				boundDescriptors.add(descriptor);
			}
		}