diff --git a/htdocs/core/modules/mrp/mod_mo_advanced.php b/htdocs/core/modules/mrp/mod_mo_advanced.php
index 186caca619a..6f8dfe92073 100644
--- a/htdocs/core/modules/mrp/mod_mo_advanced.php
+++ b/htdocs/core/modules/mrp/mod_mo_advanced.php
@@ -4,6 +4,7 @@
  * Copyright (C) 2005-2009  Regis Houssin               <regis.houssin@inodbox.com>
  * Copyright (C) 2008       Raphael Bertrand (Resultic) <raphael.bertrand@resultic.fr>
  * Copyright (C) 2019       Frédéric France             <frederic.france@netlogic.fr>
+ * Copyright (C) 2020       Josep Lluís Amador          <joseplluis@lliuretic.cat>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -68,7 +69,7 @@ class mod_mo_advanced extends ModeleNumRefMos
 		$texte .= '<form action="'.$_SERVER["PHP_SELF"].'" method="POST">';
 		$texte .= '<input type="hidden" name="token" value="'.newToken().'">';
 		$texte .= '<input type="hidden" name="action" value="updateMask">';
-		$texte .= '<input type="hidden" name="maskconstBom" value="MRP_MO_ADVANCED_MASK">';
+		$texte .= '<input type="hidden" name="maskconstMo" value="MRP_MO_ADVANCED_MASK">';
 		$texte .= '<table class="nobordernopadding" width="100%">';
 
 		$tooltip = $langs->trans("GenericMaskCodes", $langs->transnoentities("Mo"), $langs->transnoentities("Mo"));