Bug 261147 [CommonNavigator] Navigator label provider uses inconsistent methods to do the same thing
In NavigatorContentServiceLabelProvider some of the methods use findContentExtensionsWithPossibleChild and others use findRelevantLabelProvider. The latter is better and they should all use that one.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentServiceLabelProvider.java
*            A property of the given element that could be a label provider
	 * @return True if any of the extensions enabled on anElement consider aProperty a
	 *         label-changing property.
	 * @see org.eclipse.jface.viewers.IBaseLabelProvider#isLabelProperty(java.lang.Object,
	 *      java.lang.String)
	 */
	public boolean isLabelProperty(Object anElement, String aProperty) {
		boolean result = false;
		ILabelProvider[] labelProviders = contentService.findRelevantLabelProviders(anElement);
		for (int i = 0; i < labelProviders.length && !result; i++) {
			result = labelProviders[i].isLabelProperty(anElement, aProperty);
		}
		return result;
	}
	/**
	 * <p>
	 * Label provider listeners are currently supported.
	 * </p>
	 * 
	 * {@inheritDoc}
	 * @see org.eclipse.jface.viewers.IBaseLabelProvider#addListener(org.eclipse.jface.viewers.ILabelProviderListener)
	 */
	public void addListener(ILabelProviderListener aListener) {
		addListenerObject(aListener);
	}
	/**
	 * <p>
	 * Label provider listeners are currently supported.
	 * </p>
	 *