Ticket #15667: class-wp-walker.php.diff

src/wp-includes/class-wp-walker.php

@@ -219 +219 @@
                  * When none of the elements is top level.
                  * Assume the first one must be root of the sub elements.
                  */
-                if ( empty($top_level_elements) ) {
+                if ( empty($top_level_elements) && $max_depth > 1 ) {
 
                         $first = array_slice( $elements, 0, 1 );
                         $root = $first[0];