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
/**
	 * Returns whether this viewer has any filters.
	 * @return boolean
	 */
	protected boolean hasFilters() {
		return filters != null && filters.size() > 0;
	}
	/**
	 * Refreshes this viewer starting at the given element.
	 * 
	 * @param element
	 *            the element
	 */
	protected abstract void internalRefresh(Object element);
	/**
	 * Refreshes this viewer starting at the given element. Labels are updated
	 * as described in <code>refresh(boolean updateLabels)</code>.
	 * <p>
	 * The default implementation simply calls
	 * <code>internalRefresh(element)</code>, ignoring
	 * <code>updateLabels</code>.
	 * <p>
	 * If this method is overridden to do the actual refresh, then
	 * <code>internalRefresh(Object element)</code> should simply call
	 * <code>internalRefresh(element, true)</code>.
	 * 
	 * @param element
	 *            the element
	 * @param updateLabels
	 *            <code>true</code> to update labels for existing elements,