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.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
* <code>IDoubleClickListener</code>).
	 * 
	 * @see #fireDoubleClick
	 */
	private ListenerList doubleClickListeners = new ListenerList();
	/**
	 * List of open listeners (element type:
	 * <code>ISelectionActivateListener</code>).
	 * 
	 * @see #fireOpen
	 */
	private ListenerList openListeners = new ListenerList();
	/**
	 * List of post selection listeners (element type:
	 * <code>ISelectionActivateListener</code>).
	 * 
	 * @see #firePostSelectionChanged
	 */
	private ListenerList postSelectionChangedListeners = new ListenerList();
	/**
	 * The colorAndFontCollector is an object used by viewers that
	 * support the IColorProvider, the IFontProvider and/or the 
	 * IViewerLabelProvider for color and font updates.
	 * Initialize it to have no color or font providing
	 * initially.
	 * @since 3.1
	 */
	private ColorAndFontCollector colorAndFontCollector = new ColorAndFontCollector();