diff --git a/addons/mail/static/src/js/mail.js b/addons/mail/static/src/js/mail.js
index 28ba0e66923..6a409782117 100644
--- a/addons/mail/static/src/js/mail.js
+++ b/addons/mail/static/src/js/mail.js
@@ -1411,7 +1411,7 @@ openerp.mail = function (session) {
                 'show_record_name' : false,
                 'show_compose_message' : false,
                 'show_compact_message' : false,
-                'message_ids': [],
+                'message_ids': undefined,
                 'no_message': false
             }, options);