Bug 287103 [CommonNavigator] contentServiceLabelProvider doesn't properly implement overrides
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
return null;
		
		NavigatorContentDescriptor src = (NavigatorContentDescriptor) contributionMemory.get(element);
		if (src != null)
			return src;
		return (NavigatorContentDescriptor) structuredViewerManager.getData(element);
	}
	/**
	 * 
	 */
	public static final boolean CONSIDER_OVERRIDES = true;
	
	/**
	 * Search for extensions that declare the given element in their
	 * <b>triggerPoints</b> expression.
	 * 
	 * @param anElement
	 *            The element to use in the query
	 * @param considerOverrides 
	 * 
	 * @return The set of {@link INavigatorContentDescriptor}s that are
	 *         <i>visible</i> and <i>active</i> for this content service and
	 *         have a <b>triggerPoints</b> expression that is <i>enabled</i> for
	 *         the given element.
	 */
	public Set findDescriptorsByTriggerPoint(Object anElement, boolean considerOverrides) {
		
		
		NavigatorContentDescriptor descriptor = getSourceOfContribution(anElement);
		Set result = new TreeSet(ExtensionPriorityComparator.INSTANCE);