diff --git a/htdocs/core/actions_addupdatedelete.inc.php b/htdocs/core/actions_addupdatedelete.inc.php
index fb4461f94e3..b90f3c8ebd0 100644
--- a/htdocs/core/actions_addupdatedelete.inc.php
+++ b/htdocs/core/actions_addupdatedelete.inc.php
@@ -31,6 +31,11 @@
 // $noback may be defined
 // $triggermodname may be defined
 
+$hidedetails = isset($hidedetails) ? $hidedetails : '';
+$hidedesc = isset($hidedesc) ? $hidedesc : '';
+$hideref = isset($hideref) ? $hideref : '';
+
+
 if (!empty($permissionedit) && empty($permissiontoadd)) {
 	$permissiontoadd = $permissionedit; // For backward compatibility
 }
@@ -381,10 +386,10 @@ if ($action == 'confirm_validate' && $confirm == 'yes' && $permissiontoadd) {
 			if (method_exists($object, 'generateDocument')) {
 				$outputlangs = $langs;
 				$newlang = '';
-				if ($conf->global->MAIN_MULTILANGS && empty($newlang) && GETPOST('lang_id', 'aZ09')) {
+				if (!empty($conf->global->MAIN_MULTILANGS) && empty($newlang) && GETPOST('lang_id', 'aZ09')) {
 					$newlang = GETPOST('lang_id', 'aZ09');
 				}
-				if ($conf->global->MAIN_MULTILANGS && empty($newlang)) {
+				if (!empty($conf->global->MAIN_MULTILANGS) && empty($newlang)) {
 					$newlang = $object->thirdparty->default_lang;
 				}
 				if (!empty($newlang)) {