diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index 28dbe2332a7..b7a5b73145c 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -169,6 +169,7 @@ class MailThread(models.AbstractModel):
     @api.multi
     def _get_message_unread(self):
         res = dict((res_id, 0) for res_id in self.ids)
+        partner_id = self.env.user.partner_id.id
 
         # search for unread messages, directly in SQL to improve performances
         self._cr.execute(""" SELECT msg.res_id FROM mail_message msg
@@ -176,8 +177,8 @@ class MailThread(models.AbstractModel):
                              ON rel.mail_message_id = msg.id
                              RIGHT JOIN mail_channel_partner cp
                              ON (cp.channel_id = rel.mail_channel_id AND cp.partner_id = %s AND (cp.seen_message_id < msg.id))
-                             WHERE msg.model = %s AND msg.res_id in %s""",
-                         (self.env.user.partner_id.id, self._name, tuple(self.ids),))
+                             WHERE msg.model = %s AND msg.res_id in %s AND msg.author_id != %s""",
+                         (partner_id, self._name, tuple(self.ids), partner_id,))
         for result in self._cr.fetchall():
             res[result[0]] += 1
 
diff --git a/addons/mail/static/src/js/chat_manager.js b/addons/mail/static/src/js/chat_manager.js
index ec66cdde362..34559eeaad8 100644
--- a/addons/mail/static/src/js/chat_manager.js
+++ b/addons/mail/static/src/js/chat_manager.js
@@ -133,7 +133,7 @@ function add_message (data, options) {
 
     if (!msg) {
         msg = make_message(data);
-        // Keep the array ordered by date when inserting the new message
+        // Keep the array ordered by id when inserting the new message
         messages.splice(_.sortedIndex(messages, msg, 'id'), 0, msg);
         _.each(msg.channel_ids, function (channel_id) {
             var channel = chat_manager.get_channel(channel_id);
@@ -807,6 +807,21 @@ var chat_manager = {
         return chat_unread_counter;
     },
 
+    get_last_seen_message: function (channel) {
+        if (channel.last_seen_message_id) {
+            var messages = channel.cache['[]'].messages;
+            var msg = _.findWhere(messages, {id: channel.last_seen_message_id});
+            if (msg) {
+                var i = _.sortedIndex(messages, msg, 'id') + 1;
+                while (i < messages.length && messages[i].author_id && messages[i].author_id[0] === session.partner_id) {
+                    msg = messages[i];
+                    i++;
+                }
+                return msg;
+            }
+        }
+    },
+
     get_discuss_ids: function () {
         return discuss_ids;
     },
diff --git a/addons/mail/static/src/js/client_action.js b/addons/mail/static/src/js/client_action.js
index 38cc26e8997..e091590faa1 100644
--- a/addons/mail/static/src/js/client_action.js
+++ b/addons/mail/static/src/js/client_action.js
@@ -423,13 +423,11 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
         // Compute position of the 'New messages' separator, only once when joining
         // a channel to keep it in the thread when new messages arrive
         if (_.isUndefined(this.messages_separator_position)) {
-            var msg_id = this.last_seen_message_id;
             if (!this.unread_counter) {
                 this.messages_separator_position = false; // no unread message -> don't display separator
-            } else if ((msg_id === false) || !_.findWhere(messages, {id: msg_id})) {
-                this.messages_separator_position = 'top'; // all displayed messages are unread
             } else {
-                this.messages_separator_position = msg_id; // last read message is msg_id
+                var msg = chat_manager.get_last_seen_message(this.channel);
+                this.messages_separator_position = msg ? msg.id : 'top';
             }
         }
         return {