Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
*            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);
	}
	/**
	 * Remember that the elements in the given array came from the given source
	 * 
	 * @param source
	 *            The descriptor of the extension that contributed the set of
	 *            elements.
	 * @param elements
	 *            An array of elements from the given source.
	 */
	public synchronized void rememberContribution(
			NavigatorContentDescriptor source, Object[] elements) {
		if (source != null && elements != null)
			for (int i = 0; i < elements.length; i++)
				getContributionMemory().put(elements[i], source);
	}
	/**
	 * Remember that the elements in the given array came from the given source
	 * 
	 * @param source