Bug 287103 [CommonNavigator] contentServiceLabelProvider doesn't properly implement overrides
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentServiceContentProvider.java
private Set findParents(Object anElement) {
		Set descriptors = contentService.findDescriptorsWithPossibleChild(
				anElement, false);
		Set parents = new LinkedHashSet();
		NavigatorContentDescriptor foundDescriptor;
		NavigatorContentExtension foundExtension;
		Object parent = null;
		for (Iterator itr = descriptors.iterator(); itr.hasNext();) {
			foundDescriptor = (NavigatorContentDescriptor) itr.next();
			foundExtension = contentService.getExtension(foundDescriptor);
			try {
				if (!isOverridingDescriptorInSet(
						foundExtension.getDescriptor(), descriptors)) {
					
					if (foundExtension.getContentProvider() instanceof ITreePathContentProvider) {
						/*
						 * but we use the safe version to automatically handle
						 * errors
						 */
						TreePath[] parentTreePaths = ((ITreePathContentProvider) foundExtension
								.internalGetContentProvider())
								.getParents(anElement);
						for (int i = 0; i < parentTreePaths.length; i++) {
							parent = parentTreePaths[i].getLastSegment();
							if ((parent = findParent(foundExtension, anElement,
									parent)) != null)
								parents.add(parent);
						}
					} else {
						parent = foundExtension.internalGetContentProvider()