Fix: (Agenda) Allowed if link to third party is empty

htdocs/core/lib/security.lib.php

@@ -375,7 +375,7 @@ function checkUserAccessToObject($user, $featuresarray, $objectid=0, $tableandsh
 
 		$check = array('adherent','banque','user','usergroup','produit','service','produit|service','categorie'); // Test on entity only (Objects with no link to company)
 		$checksoc = array('societe');	 // Test for societe object
-		$checkother = array('contact');	 // Test on entity and link to societe. Allowed if link is empty (Ex: contacts...).
+		$checkother = array('contact','agenda');	 // Test on entity and link to third party. Allowed if link is empty (Ex: contacts...).
 		$checkproject = array('projet','project'); // Test for project object
 		$checktask = array('projet_task');
 		$nocheck = array('barcode','stock','fournisseur');	// No test