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
this.comparer = comparer;
		if (elementMap != null) {
			elementMap = new CustomHashtable(elementMap, comparer);
		}
	}
	/**
	 * NON-API - to be removed - see bug 200214
	 * Enable or disable the preserve selection behavior of this viewer. The
	 * default is that the viewer attempts to preserve the selection across
	 * update operations. This is an advanced option, to support clients that
	 * manage the selection without relying on the viewer, or clients running
	 * into performance problems when using viewers and {@link SWT#VIRTUAL}.
	 * Note that this method has been introduced in 3.5 and that trying to
	 * disable the selection behavior may not be possible for all subclasses of
	 * <code>StructuredViewer</code>, or may cause program errors. This method
	 * is supported for {@link TableViewer}, {@link TreeViewer},
	 * {@link ListViewer}, {@link CheckboxTableViewer},
	 * {@link CheckboxTreeViewer}, and {@link ComboViewer}, but no promises are
	 * made for other subclasses of StructuredViewer, or subclasses of the
	 * listed viewer classes.
	 * 
	 * @param preserve
	 *            <code>true</code> if selection should be preserved,
	 *            <code>false</code> otherwise
	 */
	void setPreserveSelection(boolean preserve) {
		this.preserveSelection = preserve;
	}
	/**
	 * NON-API - to be removed - see bug 200214