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
Color foreground = null;
		Color background = null;
		Font font = null;
		boolean usedDecorators = false;
		/**
		 * Create a new instance of the receiver with
		 * no color and font provider.	
		 */
		public ColorAndFontCollector(){
			super();
		}
		
		/**
		 * Clear all of the results.
		 */
		public void clear() {
			foreground = null;
			background = null;
			font = null;
			usedDecorators = false;
		}
		
		/**
		 * Set the initial fonts and colors for the element from the