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
filters = new ArrayList();
		}
		filters.add(filter);
		refresh();
	}
	/**
	 * Asserts that the given array of elements is itself non- <code>null</code>
	 * and contains no <code>null</code> elements.
	 * 
	 * @param elements
	 *            the array to check
	 */
	protected void assertElementsNotNull(Object[] elements) {
		Assert.isNotNull(elements);
		for (int i = 0, n = elements.length; i < n; ++i) {
			Assert.isNotNull(elements[i]);
		}
	}
	/**
	 * Associates the given element with the given widget. Sets the given item's
	 * data to be the element, and maps the element to the item in the element
	 * map (if enabled).
	 * 
	 * @param element
	 *            the element
	 * @param item
	 *            the widget
	 */
	protected void associate(Object element, Item item) {
		Object data = item.getData();