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
*/
	protected abstract void setSelectionToWidget(List l, boolean reveal);
	/**
	 * Converts the selection to a <code>List</code> and calls
	 * <code>setSelectionToWidget(List, boolean)</code>. The selection is
	 * expected to be an <code>IStructuredSelection</code> of elements. If
	 * not, the selection is cleared.
	 * <p>
	 * Subclasses do not typically override this method, but implement
	 * <code>setSelectionToWidget(List, boolean)</code> instead.
	 * 
	 * @param selection
	 *            an IStructuredSelection of elements
	 * @param reveal
	 *            <code>true</code> to reveal the first element in the
	 *            selection, or <code>false</code> otherwise
	 */
	protected void setSelectionToWidget(ISelection selection, boolean reveal) {
		if (selection instanceof IStructuredSelection) {
			setSelectionToWidget(((IStructuredSelection) selection).toList(), reveal);
		} else {
			setSelectionToWidget((List) null, reveal);
		}
	}
	/**
	 * Sets this viewer's sorter and triggers refiltering and resorting of this
	 * viewer's element. Passing <code>null</code> turns sorting off.  
     * <p>
     * It is recommended to use <code>setComparator()</code> instead.
     * </p>