Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorContentDescriptor.java
*/
	public boolean isPossibleChild(Object anElement) {
		if ((enablement == null && possibleChildren == null)
				|| anElement == null)
			return false;
		try {
			if (possibleChildren != null)
				return (possibleChildren.evaluate(new EvaluationContext(null,
						anElement)) == EvaluationResult.TRUE);
			else if (enablement != null)
				return (enablement.evaluate(new EvaluationContext(null,
						anElement)) == EvaluationResult.TRUE);
		} catch (CoreException e) {
			NavigatorPlugin.logError(0, e.getMessage(), e);
		}
		return false;
	}
	/**
	 * 
	 * Does not force the creation of the set of overriding extensions.
	 * 
	 * @return True if this extension has overridding extensions.
	 */
	public boolean hasOverridingExtensions() {
		return overridingExtensions != null && overridingExtensions.size() > 0;
	}
	/**
	 * @return The set of overridding extensions (of type
	 *         {@link INavigatorContentDescriptor}
	 */