Bug 302791 [CommonNavigator] Associated editor does not close when deleting resource (editorInput) through CommonNavigator
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorContentDescriptor.java
* Determine if this content extension would be able to provide children for
	 * the given element.
	 * 
	 * @param anElement
	 *            The element that should be used for the evaluation.
	 * @return True if and only if the extension is enabled for the element.
	 */
	public boolean isTriggerPoint(Object anElement) {
		if (enablement == null || anElement == null) {
			return false;
		}
		try {
			IEvaluationContext context = NavigatorPlugin.getEvalContext(anElement);
			return (enablement.evaluate(context) == EvaluationResult.TRUE);
		} catch (CoreException e) {
			NavigatorPlugin.logError(0, e.getMessage(), e);
		}
		return false;
	}
	/**
	 * Determine if this content extension could provide the given element as a
	 * child.
	 * 
	 * <p>
	 * This method is used to determine what the parent of an element could be
	 * for Link with Editor support.
	 * </p>
	 * 
	 * @param anElement
	 *            The element that should be used for the evaluation.