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
unmapElement(element, item);
		item.setData(null);
	}
	/**
	 * Returns the widget in this viewer's control which represents the given
	 * element if it is the viewer's input.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.
	 * </p>
	 * 
	 * @param element
	 * @return the corresponding widget, or <code>null</code> if none
	 */
	protected abstract Widget doFindInputItem(Object element);
	/**
	 * Returns the widget in this viewer's control which represent the given
	 * element. This method searches all the children of the input element.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.
	 * </p>
	 * 
	 * @param element
	 * @return the corresponding widget, or <code>null</code> if none
	 */
	protected abstract Widget doFindItem(Object element);
	/**
	 * Copies the attributes of the given element into the given SWT item. The
	 * element map is updated according to the value of <code>fullMap</code>.