diff --git a/htdocs/categories/admin/categorie.php b/htdocs/categories/admin/categorie.php
index 0483caa29ae..23ebc01f3e2 100644
--- a/htdocs/categories/admin/categorie.php
+++ b/htdocs/categories/admin/categorie.php
@@ -1,6 +1,7 @@
 <?php
-/* Copyright (C) 2008-2011 Laurent Destailleur  <eldy@users.sourceforge.net>
- * Copyright (C) 2013 		Florian Henry  <florian.henry@open-concept.pro>
+/* Copyright (C) 2008-2011	Laurent Destailleur  <eldy@users.sourceforge.net>
+ * Copyright (C) 2013 		Florian Henry  		<florian.henry@open-concept.pro>
+ * Copyright (C) 2015 		Juanjo Menent		<jmenent@2byte.es>
  *
  * 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
@@ -107,11 +108,11 @@ if ($conf->use_javascript_ajax)
 }
 else
 {
-	if($conf->global->CATEGORIE_RECURSIV_ADD == 0)
+	if (empty($conf->global->CATEGORIE_RECURSIV_ADD))
 	{
 		print '<a href="'.$_SERVER['PHP_SELF'].'?action=set_CATEGORIE_RECURSIV_ADD">'.img_picto($langs->trans("Disabled"),'off').'</a>';
 	}
-	else if($conf->global->CATEGORIE_RECURSIV_ADD == 1)
+	else
 	{
 		print '<a href="'.$_SERVER['PHP_SELF'].'?action=del_CATEGORIE_RECURSIV_ADD">'.img_picto($langs->trans("Enabled"),'on').'</a>';
 	}
diff --git a/htdocs/commande/class/commande.class.php b/htdocs/commande/class/commande.class.php
index 96e41962f9b..18c8b554637 100644
--- a/htdocs/commande/class/commande.class.php
+++ b/htdocs/commande/class/commande.class.php
@@ -1252,7 +1252,7 @@ class Commande extends CommonOrder
 				$result=$product->fetch($fk_product);
 				$product_type=$product->type;
 
-				if($conf->global->STOCK_MUST_BE_ENOUGH_FOR_ORDER && $product_type == 0 && $product->stock_reel < $qty)
+				if (! empty($conf->global->STOCK_MUST_BE_ENOUGH_FOR_ORDER) && $product_type == 0 && $product->stock_reel < $qty)
 				{
 					$this->error=$langs->trans('ErrorStockIsNotEnough');
 					dol_syslog(get_class($this)."::addline error=Product ".$product->ref.": ".$this->error, LOG_ERR);
diff --git a/htdocs/compta/facture/class/facture.class.php b/htdocs/compta/facture/class/facture.class.php
index 59acd0b81f2..a347ccdbca8 100644
--- a/htdocs/compta/facture/class/facture.class.php
+++ b/htdocs/compta/facture/class/facture.class.php
@@ -2179,7 +2179,7 @@ class Facture extends CommonInvoice
 				$result=$product->fetch($fk_product);
 				$product_type=$product->type;
 
-				if($conf->global->STOCK_MUST_BE_ENOUGH_FOR_INVOICE && $product_type == 0 && $product->stock_reel < $qty) {
+				if (! empty($conf->global->STOCK_MUST_BE_ENOUGH_FOR_INVOICE) && $product_type == 0 && $product->stock_reel < $qty) {
 					$this->error=$langs->trans('ErrorStockIsNotEnough');
 					$this->db->rollback();
 					return -3;