$form['description']['#markup']='<p>This form has been disabled by the node_access_rebuild_progressive module.</p>';
$form['description']['#markup'].='<p>You can manually rebuild the permissions using Drush: <strong>drush node-access-rebuild-progressive</strong>.</p>';
if($config->get('cron')){
$form['description']['#markup'].='<p>Else they will be rebuilt incrementally during Drupal cron run.</p>';