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
ISelection newSelection = getSelection();
			if (!newSelection.equals(oldSelection)) {
				handleInvalidSelection(oldSelection, newSelection);
			}
		}
	}
	
	/*
	 * Non-Javadoc. Method declared on Viewer.
	 */
	public void refresh() {
		refresh(getRoot());
	}
	/**
	 * Refreshes this viewer with information freshly obtained from this
	 * viewer's model. If <code>updateLabels</code> is <code>true</code>
	 * then labels for otherwise unaffected elements are updated as well.
	 * Otherwise, it assumes labels for existing elements are unchanged, and
	 * labels are only obtained as needed (for example, for new elements).
	 * <p>
	 * Calling <code>refresh(true)</code> has the same effect as
	 * <code>refresh()</code>.
	 * <p>
	 * Note that the implementation may still obtain labels for existing
	 * elements even if <code>updateLabels</code> is false. The intent is
	 * simply to allow optimization where possible.
	 * 
	 * @param updateLabels
	 *            <code>true</code> to update labels for existing elements,