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
return elements;
	}
	/**
	 * Finds the widget which represents the given element.
	 * <p>
	 * The default implementation of this method tries first to find the widget
	 * for the given element assuming that it is the viewer's input; this is
	 * done by calling <code>doFindInputItem</code>. If it is not found
	 * there, it is looked up in the internal element map provided that this
	 * feature has been enabled. If the element map is disabled, the widget is
	 * found via <code>doFindInputItem</code>.
	 * </p>
	 * 
	 * @param element
	 *            the element
	 * @return the corresponding widget, or <code>null</code> if none
	 */
	protected final Widget findItem(Object element) {
		Widget[] result = findItems(element);
		return result.length == 0 ? null : result[0];
	}
	/**
	 * Finds the widgets which represent the given element. The returned array
	 * must not be changed by clients; it might change upon calling other
	 * methods on this viewer.
	 * <p>
	 * This method was introduced to support multiple equal elements in a viewer
	 * (@see {@link AbstractTreeViewer}). Multiple equal elements are only
	 * supported if the element map is enabled by calling
	 * {@link #setUseHashlookup(boolean)} and passing <code>true</code>.