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/sorters/CommonSorterDescriptor.java
if (children.length == 1) {
			parentExpression = new CustomAndExpression(children[0]);
		}
	}
	/**
	 * 
	 * @return An identifier used to determine whether the sorter is visible.
	 *         May not be unique.
	 */
	public String getId() {
		return id;
	}
 
	/**
	 * 
	 * @param aParent
	 *            An element from the viewer
	 * @return True if and only if this CommonSorter can sort the children of
	 *         the given parent.
	 */
	public boolean isEnabledForParent(Object aParent) {
		if(aParent == null) {
			return false;
		}
		if (parentExpression != null) {
			IEvaluationContext context = NavigatorPlugin.getEvalContext(aParent);
			try {
				return parentExpression.evaluate(context) == EvaluationResult.TRUE;
			} catch (CoreException e) {
				NavigatorPlugin.logError(0, e.getMessage(), e);