diff --git a/htdocs/contact/document.php b/htdocs/contact/document.php
index b081582337e..ad8bbb68e5f 100644
--- a/htdocs/contact/document.php
+++ b/htdocs/contact/document.php
@@ -63,8 +63,8 @@ $offset = $conf->liste_limit * $page;
 $pageprev = $page - 1;
 $pagenext = $page + 1;
 
- if (isset($conf->global->MAIN_DOC_SORT_FIELD)){$sortfield=$conf->global->MAIN_DOC_SORT_FIELD;}
- if (isset($conf->global->MAIN_DOC_SORT_ORDER)){$sortorder=$conf->global->MAIN_DOC_SORT_ORDER;}
+ if (! empty($conf->global->MAIN_DOC_SORT_FIELD)) { $sortfield=$conf->global->MAIN_DOC_SORT_FIELD; }
+ if (! empty($conf->global->MAIN_DOC_SORT_ORDER)) { $sortorder=$conf->global->MAIN_DOC_SORT_ORDER; }
 
 if (! $sortorder) $sortorder="ASC";
 if (! $sortfield) $sortfield="name";