diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index 835ad698a1b..d98625db1cc 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -1335,7 +1335,11 @@ abstract class CommonObject
         if (empty($this->isnolinkedbythird) && !$user->rights->societe->client->voir) $sql.= " LEFT JOIN ".MAIN_DB_PREFIX."societe_commerciaux as sc ON ".$alias.".rowid = sc.fk_soc";
         $sql.= " WHERE te.".$fieldid." > '".$this->db->escape($this->ref)."'";  // ->ref must always be defined (set to id if field does not exists)
         if (empty($this->isnolinkedbythird) && !$user->rights->societe->client->voir) $sql.= " AND sc.fk_user = " .$user->id;
-        if (! empty($filter)) $sql.=" AND ".$filter;
+        if (! empty($filter))
+        {
+            if (! preg_match('/^\s*AND/i', $filter)) $sql.=" AND ";   // For backward compatibility
+            $sql.=$filter;
+        }
         if (isset($this->ismultientitymanaged) && $this->ismultientitymanaged == 2 || ($this->element != 'societe' && empty($this->isnolinkedbythird) && !$user->rights->societe->client->voir)) $sql.= ' AND te.fk_soc = s.rowid';			// If we need to link to societe to limit select to entity
         if (isset($this->ismultientitymanaged) && $this->ismultientitymanaged == 1) $sql.= ' AND te.entity IN ('.getEntity($this->element, 1).')';
         // Rem: Bug in some mysql version: SELECT MIN(rowid) FROM llx_socpeople WHERE rowid > 1 when one row in database with rowid=1, returns 1 instead of null