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 (filters != null) {
			for (Iterator iter = filters.iterator(); iter.hasNext();) {
				ViewerFilter f = (ViewerFilter) iter.next();
				result = f.filter(this, parent, result);
			}
		}
		return result;
	}
	/**
	 * Returns this viewer's filters.
	 * 
	 * @return an array of viewer filters
	 * @see StructuredViewer#setFilters(ViewerFilter[])
	 */
	public ViewerFilter[] getFilters() {
		if (filters == null) {
			return new ViewerFilter[0];
		}
		ViewerFilter[] result = new ViewerFilter[filters.size()];
		filters.toArray(result);
		return result;
	}
	/**
	 * Returns the item at the given display-relative coordinates, or
	 * <code>null</code> if there is no item at that location or 
	 * the underlying SWT-Control is not made up of {@link Item} 
	 * (e.g {@link ListViewer}) 
	 * <p>
	 * The default implementation of this method returns <code>null</code>.
	 * </p>