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.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/StructuredViewerManager.java
this.viewerDataMap = viewerDataMap;
			}
			public void associate(Object element, Item item) {
				NavigatorContentDescriptor desc = contentService.getContribution(element);
				synchronized (viewerDataMap) {
					if (viewerDataMap.containsKey(element)) {
						if (Policy.DEBUG_VIEWER_MAP)
							System.out.println("associate: SKIPPED " + element + " item: " + item + " desc: " + desc + " FOUND"); 
						return;
					}
					viewerDataMap.put(element, desc);
					if (Policy.DEBUG_VIEWER_MAP)
						System.out.println("associate: " + element + " item: " + item + " desc: " + desc); 
				}
			}
			public void disassociate(Item item) {
				synchronized (viewerDataMap) {
					if (Policy.DEBUG_VIEWER_MAP)
						System.out.println("disassociate:  item: " + item + " object: " + item.getData()); 
					viewerDataMap.remove(item.getData());
				}
			}
		}
		protected static void hookAssociateListener(StructuredViewer v, Map viewerDataMap, NavigatorContentService contentService) {
			StructuredViewerInternals.setAssociateListener(v, new Listener(contentService, viewerDataMap));
		}
	}
	
	/**
	 * @param element