diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index af156d0442f0e..5c57d26630128 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -13055,7 +13055,7 @@ function getActionCommEcmList($object)
  * 		@param	Translate	       $langs		   Object langs
  * 		@param	DoliDB		       $db			   Object db
  * 		@param	mixed			   $filterobj	   Filter on object Adherent|Societe|Project|Product|CommandeFournisseur|Dolresource|Ticket|... to list events linked to an object
- * 		@param	Contact		       $objcon		   Filter on object contact to filter events on a contact
+ * 		@param	Contact|null       $objcon		   Filter on object contact to filter events on a contact
  *      @param  int			       $noprint        Return string but does not output it
  *      @param  string		       $actioncode     Filter on actioncode
  *      @param  string             $donetodo       Filter on event 'done' or 'todo' or ''=nofilter (all).
@@ -13064,7 +13064,7 @@ function getActionCommEcmList($object)
  *      @param  string             $sortorder      Sort order
  *      @return	string|void				           Return html part or void if noprint is 1
  */
-function show_actions_messaging($conf, $langs, $db, $filterobj, $objcon = '', $noprint = 0, $actioncode = '', $donetodo = 'done', $filters = array(), $sortfield = 'a.datep,a.id', $sortorder = 'DESC')
+function show_actions_messaging($conf, $langs, $db, $filterobj, $objcon = null, $noprint = 0, $actioncode = '', $donetodo = 'done', $filters = array(), $sortfield = 'a.datep,a.id', $sortorder = 'DESC')
 {
 	global $user, $conf;
 	global $form;