Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorContentExtension.java
NavigatorContentDescriptor overriddingDescriptor;
		Set overridingExtensions = new HashSet();
		for (Iterator contentDescriptorsItr = descriptor
				.getOverriddingExtensions().iterator(); contentDescriptorsItr
				.hasNext();) {
			overriddingDescriptor = (NavigatorContentDescriptor) contentDescriptorsItr
					.next();
			if (contentService.isActive(overriddingDescriptor.getId())
					&& contentService.isVisible(overriddingDescriptor.getId())
					&& overriddingDescriptor.isTriggerPoint(anElement)) {
				overridingExtensions.add(contentService
						.getExtension(overriddingDescriptor));
			}
		}
		if (overridingExtensions.size() == 0)
			return NO_EXTENSIONS;
		return (NavigatorContentExtension[]) overridingExtensions
				.toArray(new NavigatorContentExtension[overridingExtensions
						.size()]);
	}
	/**
	 * 
	 * @param anElement
	 *            The element for the query.
	 * @return Returns the overridingExtensions.
	 */
	public NavigatorContentExtension[] getOverridingExtensionsForPossibleChild(
			Object anElement) {
		if (!descriptor.hasOverridingExtensions())
			return NO_EXTENSIONS;