Bug 287103 [CommonNavigator] contentServiceLabelProvider doesn't properly implement overrides
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
*         <i>visible</i> and <i>active</i> for this content service and
	 *         have a <b>possibleChildren</b> expression that is <i>enabled</i>
	 *         for the given element.
	 */
	public Set findContentExtensionsWithPossibleChild(Object anElement) {
		return findContentExtensionsWithPossibleChild(anElement, true);
	}
	/**
	 * Search for extensions that declare the given element in their
	 * <b>possibleChildren</b> expression.
	 * 
	 * @param anElement
	 *            The element to use in the query
	 * @param toLoadIfNecessary
	 *            True will force the load of the extension, False will not
	 * @return The set of {@link INavigatorContentExtension}s that are
	 *         <i>visible</i> and <i>active</i> for this content service and
	 *         have a <b>possibleChildren</b> expression that is <i>enabled</i>
	 *         for the given element.
	 */
	public Set findContentExtensionsWithPossibleChild(Object anElement,
			boolean toLoadIfNecessary) {
		Set enabledDescriptors = findDescriptorsWithPossibleChild(anElement);
		return extractDescriptorInstances(enabledDescriptors, toLoadIfNecessary);
	}
	/**
	 * 
	 */
	public void resetContributionMemory() {
		contributionMemory.clear();