diff --git a/addons/mail/static/src/js/mail.js b/addons/mail/static/src/js/mail.js
index 1f2d9fda6a6..94ce41802cc 100644
--- a/addons/mail/static/src/js/mail.js
+++ b/addons/mail/static/src/js/mail.js
@@ -478,7 +478,7 @@ openerp.mail = function(session) {
                     self.thread = new mail.Thread(self, {
                         'context': {
                             'default_model': record.model,
-                            'default_id': record.res_id,
+                            'default_res_id': record.res_id,
                             'default_parent_id': record.id },
                         'message_data': record.child_ids, 'thread_level': self.options.thread_level-1,
                         'show_header_compose': false, 'show_reply': self.options.thread_level > 1,
@@ -547,9 +547,9 @@ openerp.mail = function(session) {
                 var body = comment_node.val();
                 comment_node.val('');
             }
-            return this.ds_post.call('message_post', [
-                [this.options.context.res_id], body, false, 'comment', this.options.context.parent_id]
-                ).then(this.proxy('message_fetch'));
+            return this.ds_thread.call('message_post', [
+                [this.options.context.default_res_id], body, false, 'comment', this.options.context.default_parent_id, undefined]
+                ).then(self.message_fetch());
         },
 
         /** Action: 'shows more' to fetch new messages */