diff --git a/htdocs/html.form.class.php b/htdocs/html.form.class.php
index 8c45d79ea9f..fd92d3f6b6f 100644
--- a/htdocs/html.form.class.php
+++ b/htdocs/html.form.class.php
@@ -613,20 +613,20 @@ class Form
         $sql.= " FROM ".MAIN_DB_PREFIX."product as p ";
         if ($conf->categorie->enabled && !$user->rights->categorie->voir)
         {
-           $sql .= ", ".MAIN_DB_PREFIX."categorie_product as cp";
-           $sql .= ", ".MAIN_DB_PREFIX."categorie as c";
+           $sql .= " LEFT JOIN ".MAIN_DB_PREFIX."categorie_product as cp ON cp.fk_product = p.rowid";
+           $sql .= " LEFT JOIN ".MAIN_DB_PREFIX."categorie as c ON cp.fk_categorie = c.rowid";
         }
         $sql.= " WHERE p.envente = 1";
         if ($conf->categorie->enabled && !$user->rights->categorie->voir)
         {
-           $sql .= " AND cp.fk_product = p.rowid";
-           $sql .= " AND cp.fk_categorie = c.rowid AND c.visible = 1";
+        	$sql.= ' AND IFNULL(c.visible,1)=1';
         }
         if ($filtretype && $filtretype != '') $sql.=" AND p.fk_product_type=".$filtretype;
         $sql.= " ORDER BY p.nbvente DESC";
         if ($limit) $sql.= " LIMIT $limit";
-    
+
         $result=$this->db->query($sql);
+        if (! $result) dolibarr_print_error($this->db);
         
         // Multilang : on construit une liste des traductions des produits listés
         $sqld = "SELECT d.fk_product, d.label";
diff --git a/htdocs/includes/boxes/box_services_vendus.php b/htdocs/includes/boxes/box_services_vendus.php
index 39b799e12f5..08c72fa6c8d 100644
--- a/htdocs/includes/boxes/box_services_vendus.php
+++ b/htdocs/includes/boxes/box_services_vendus.php
@@ -1,6 +1,6 @@
 <?php
 /* Copyright (C) 2003      Rodolphe Quiedeville <rodolphe@quiedeville.org>
- * Copyright (C) 2005      Laurent Destailleur  <eldy@users.sourceforge.net>
+ * Copyright (C) 2005-2006 Laurent Destailleur  <eldy@users.sourceforge.net>
  * Copyright (C) 2005-2006 Regis Houssin        <regis.houssin@cap-networks.com>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -19,7 +19,6 @@
  *
  * $Id$
  * $Source$
- *
  */
 
 /**
@@ -69,17 +68,16 @@ class box_services_vendus extends ModeleBoxes {
             if (!$user->rights->commercial->client->voir && !$user->societe_id) $sql .= ", sc.fk_soc, sc.fk_user";
             $sql .= " FROM ".MAIN_DB_PREFIX."societe as s, ".MAIN_DB_PREFIX."contrat as c, ".MAIN_DB_PREFIX."contratdet as cd, ".MAIN_DB_PREFIX."product as p";
             if (!$user->rights->commercial->client->voir && !$user->societe_id) $sql .= ", ".MAIN_DB_PREFIX."societe_commerciaux as sc";
-            if ($conf->categorie->enabled && !$user->rights->categorie->voir)
-            {
-              $sql .= ", ".MAIN_DB_PREFIX."categorie_product as cp";
-              $sql .= ", ".MAIN_DB_PREFIX."categorie as ca";
-            }
+	        if ($conf->categorie->enabled && !$user->rights->categorie->voir)
+	        {
+	           $sql .= " LEFT JOIN ".MAIN_DB_PREFIX."categorie_product as cp ON cp.fk_product = p.rowid";
+	           $sql .= " LEFT JOIN ".MAIN_DB_PREFIX."categorie as ca ON cp.fk_categorie = ca.rowid";
+	        }
             $sql .= " WHERE s.idp = c.fk_soc AND c.rowid = cd.fk_contrat AND cd.fk_product = p.rowid";
             if (!$user->rights->commercial->client->voir && !$user->societe_id) $sql .= " AND s.idp = sc.fk_soc AND sc.fk_user = " .$user->id;
             if ($conf->categorie->enabled && !$user->rights->categorie->voir)
             {
-              $sql .= " AND cp.fk_product = p.rowid";
-              $sql .= " AND cp.fk_categorie = ca.rowid AND ca.visible = 1";
+				$sql.= ' AND IFNULL(ca.visible,1)=1';
             }
             if($user->societe_id)
             {
diff --git a/htdocs/product/liste.php b/htdocs/product/liste.php
index 03d5559936d..720dfa23028 100644
--- a/htdocs/product/liste.php
+++ b/htdocs/product/liste.php
@@ -79,15 +79,10 @@ $title=$langs->trans("ProductsAndServices");
 $sql = 'SELECT p.rowid, p.ref, p.label, p.price, p.fk_product_type, '.$db->pdate('p.tms').' as datem,';
 $sql.= ' p.duration, p.envente as statut';
 $sql.= ' FROM '.MAIN_DB_PREFIX.'product as p'; // '.MAIN_DB_PREFIX.'product_det as d'; //en attendant le debugage
-
 if ($catid || ($conf->categorie->enabled && !$user->rights->categorie->voir))
 {
-  $sql .= ", ".MAIN_DB_PREFIX."categorie_product as cp";
-}
-
-if ($conf->categorie->enabled && !$user->rights->categorie->voir)
-{
-	$sql .= ", ".MAIN_DB_PREFIX."categorie as c";
+	$sql .= " LEFT JOIN ".MAIN_DB_PREFIX."categorie_product as cp ON cp.fk_product = p.rowid";
+	$sql .= " LEFT JOIN ".MAIN_DB_PREFIX."categorie as c ON cp.fk_categorie = c.rowid";
 }
 
 if ($_GET["fourn_id"] > 0)
@@ -116,17 +111,13 @@ if (isset($_GET["envente"]) && strlen($_GET["envente"]) > 0)
 {
     $sql .= " AND p.envente = ".$_GET["envente"];
 }
-if($catid || ($conf->categorie->enabled && !$user->rights->categorie->voir))
-{
-    $sql .= " AND cp.fk_product = p.rowid";
-}
 if($catid)
 {
     $sql .= " AND cp.fk_categorie = ".$catid;
 }
 if ($conf->categorie->enabled && !$user->rights->categorie->voir)
 {
-	$sql .= " AND cp.fk_categorie = c.rowid AND c.visible = 1";
+	$sql.= ' AND IFNULL(c.visible,1)=1';
 }
 if ($fourn_id > 0)
 {