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.isPossibleChild(anElement)) {
				overridingExtensions.add(contentService
						.getExtension(overriddingDescriptor));
			}
		}
		if (overridingExtensions.size() == 0)
			return NO_EXTENSIONS;
		return (NavigatorContentExtension[]) overridingExtensions
				.toArray(new NavigatorContentExtension[overridingExtensions
						.size()]);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#toString()
	 */
	public String toString() {
		return descriptor.toString() + " Instance"; 
	}
}