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
* If <code>fullMap</code> is <code>true</code> then the current mapping
	 * from element to widgets is removed and the new mapping is added. If
	 * full map is <code>false</code> then only the new map gets installed.
	 * Installing only the new map is necessary in cases where only the order of
	 * elements changes but not the set of elements.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.
	 * </p>
	 * 
	 * @param item
	 * @param element element
	 * @param fullMap
	 *            <code>true</code> if mappings are added and removed, and
	 *            <code>false</code> if only the new map gets installed
	 */
	protected abstract void doUpdateItem(Widget item, Object element, boolean fullMap);
	/**
	 * Compares two elements for equality. Uses the element comparer if one has
	 * been set, otherwise uses the default <code>equals</code> method on the
	 * elements themselves.
	 * 
	 * @param elementA
	 *            the first element
	 * @param elementB
	 *            the second element
	 * @return whether elementA is equal to elementB
	 */
	protected boolean equals(Object elementA, Object elementB) {
		if (comparer == null) {