The default space now also contains objectGroups

src/datasets.php

 <?php
 require_once(__DIR__ . "/ks-datasets-database.php");
 
-$EMPTY_SPACE = '{"links":[],"nodes":[]}';
+$EMPTY_SPACE = '{"links":[],"nodes":[],"objectGroups":[]}';
 
 add_action("wp_ajax_get_space", "ks_get_space"); // Fires only for logged-in-users
 add_action("wp_ajax_nopriv_get_space", 'ks_get_space' ); // Fires for everyone