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>false</code> to only update labels as needed, assuming
	 *            that labels for existing elements are unchanged.
	 * 
	 * @since 2.0
	 */
	protected void internalRefresh(Object element, boolean updateLabels) {
		internalRefresh(element);
	}
	/**
	 * Adds the element item pair to the element map.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.
	 * </p>
	 * 
	 * @param element
	 *            the element
	 * @param item
	 *            the corresponding widget
	 */
	protected void mapElement(Object element, Widget item) {
		if (elementMap != null) {
			Object widgetOrWidgets = elementMap.get(element);
			if (widgetOrWidgets == null) {
				elementMap.put(element, item);
			} else if (widgetOrWidgets instanceof Widget) {
				if (widgetOrWidgets != item) {
					elementMap.put(element, new Widget[] {
							(Widget) widgetOrWidgets, item });
				}