diff --git a/addons/im_livechat/static/src/js/im_livechat.js b/addons/im_livechat/static/src/js/im_livechat.js
index 12142766bf1..e3609946525 100644
--- a/addons/im_livechat/static/src/js/im_livechat.js
+++ b/addons/im_livechat/static/src/js/im_livechat.js
@@ -42,6 +42,9 @@ var LivechatButton = Widget.extend({
         bus.on('notification', this, function (notification) {
             this.add_message(notification[1]);
             this.render_messages();
+            if (this.chat_window.folded) {
+                this.chat_window.update_unread(this.chat_window.unread_msgs+1);
+            }
         });
         return this._super();
     },
@@ -93,7 +96,7 @@ var LivechatButton = Widget.extend({
         var options = {
             display_stars: false,
         };
-        this.chat_window = new ChatWindow(this, channel.id, channel.name, false, options);
+        this.chat_window = new ChatWindow(this, channel.id, channel.name, false, channel.message_unread_counter, options);
         this.chat_window.appendTo($('body')).then(function () {
             self.chat_window.$el.css({right: 0, bottom: 0});
             self.$el.hide();
diff --git a/addons/mail/static/src/js/chat_manager.js b/addons/mail/static/src/js/chat_manager.js
index 239291628f0..7da3329a178 100644
--- a/addons/mail/static/src/js/chat_manager.js
+++ b/addons/mail/static/src/js/chat_manager.js
@@ -306,6 +306,11 @@ function fetch_document_messages (ids, options) {
     }
 }
 
+function update_channel_unread_counter (channel, counter) {
+    channel.unread_counter = counter;
+    chat_manager.bus.trigger("update_channel_unread_counter", channel);
+}
+
 var channel_seen = _.throttle(function (channel) {
     return ChannelModel.call('channel_seen', [[channel.id]]).then(function (last_seen_message_id) {
         channel.last_seen_message_id = last_seen_message_id;
@@ -343,7 +348,7 @@ function on_needaction_notification (message) {
 function on_channel_notification (message) {
     var channel = chat_manager.get_channel(message.channel_ids[0]);
     if (channel) {
-        channel.unread_counter++;
+        update_channel_unread_counter(channel, channel.unread_counter+1);
         add_message(message, { channel_id: channel.id, show_notification: true });
     } else {
         chat_manager.join_channel(message.channel_ids[0], {autoswitch: false}).then(function() {
@@ -492,7 +497,7 @@ var chat_manager = {
     },
     mark_channel_as_seen: function (channel) {
         if (channel.unread_counter > 0) {
-            channel.unread_counter = 0;
+            update_channel_unread_counter(channel, 0);
             channel_seen(channel);
         }
     },
diff --git a/addons/mail/static/src/js/chat_window.js b/addons/mail/static/src/js/chat_window.js
index cfc3c8c5447..8fa1e2a2536 100644
--- a/addons/mail/static/src/js/chat_window.js
+++ b/addons/mail/static/src/js/chat_window.js
@@ -16,7 +16,7 @@ return Widget.extend({
         "click .o_chat_title": "on_click_fold",
     },
 
-    init: function (parent, channel_id, title, is_folded, options) {
+    init: function (parent, channel_id, title, is_folded, unread_msgs, options) {
         this._super(parent);
         this.title = title;
         this.channel_id = channel_id;
@@ -25,7 +25,7 @@ return Widget.extend({
         this.options = _.defaults(options || {}, {
             display_stars: true,
         });
-        this.unread_msgs = -1;
+        this.unread_msgs = unread_msgs || 0;
     },
     start: function () {
         this.$content = this.$('.o_chat_content');
@@ -46,9 +46,6 @@ return Widget.extend({
         return $.when(this._super(), def);
     },
     render: function (messages) {
-        if (this.folded) {
-            this.unread_msgs++;
-        }
         this.update_header();
         this.thread.render(messages, {display_load_more: false});
     },
@@ -57,6 +54,10 @@ return Widget.extend({
             this.title + ' (' + this.unread_msgs + ')' : this.title;
         this.$('.o_chat_title').text(title);
     },
+    update_unread: function (counter) {
+        this.unread_msgs = counter;
+        this.update_header();
+    },
     scrollBottom: function () {
         this.$content.scrollTop(this.$content[0].scrollHeight);
     },
@@ -70,6 +71,7 @@ return Widget.extend({
         this.folded = !this.folded;
         if (!this.folded) {
             this.unread_msgs = 0;
+            this.trigger('messages_read');
         }
         this.fold();
     },
diff --git a/addons/mail/static/src/js/client_action.js b/addons/mail/static/src/js/client_action.js
index 7f9e3a83665..874debf6a3d 100644
--- a/addons/mail/static/src/js/client_action.js
+++ b/addons/mail/static/src/js/client_action.js
@@ -218,6 +218,7 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
                 });
                 chat_manager.bus.on('update_needaction', self, self.render_sidebar);
                 chat_manager.bus.on('unsubscribe_from_channel', self, self.render_sidebar);
+                chat_manager.bus.on('update_channel_unread_counter', self, self.render_sidebar);
             });
     },
 
diff --git a/addons/mail/static/src/js/window_manager.js b/addons/mail/static/src/js/window_manager.js
index 2326ef14dc2..22eb60f9180 100644
--- a/addons/mail/static/src/js/window_manager.js
+++ b/addons/mail/static/src/js/window_manager.js
@@ -15,12 +15,16 @@ var CHAT_WINDOW_WIDTH = 260;
 
 function open_chat (session) {
     if (!_.findWhere(chat_sessions, {id: session.id})) {
+        var channel = chat_manager.get_channel(session.id);
         var chat_session = {
             id: session.id,
             uuid: session.uuid,
             name: session.name,
-            window: new ChatWindow(web_client, session.id, session.name, session.is_folded),
+            window: new ChatWindow(web_client, session.id, session.name, session.is_folded, channel.unread_counter),
         };
+        if (!session.is_folded) {
+            chat_manager.mark_channel_as_seen(channel);
+        }
         chat_session.window.on("close_chat_session", null, function () {
             close_chat(chat_session);
             chat_manager.close_chat_session(chat_session.id);
@@ -36,6 +40,9 @@ function open_chat (session) {
         chat_session.window.on("post_message", null, function (message) {
             chat_manager.post_message(message);
         });
+        chat_session.window.on("messages_read", null, function () {
+            chat_manager.mark_channel_as_seen(channel);
+        });
 
         chat_sessions.push(chat_session);
         chat_session.window.appendTo($('body'))
@@ -74,6 +81,9 @@ function reposition_windows () {
 function update_sessions (message, scrollBottom) {
     _.each(chat_sessions, function (session) {
         if (_.contains(message.channel_ids, session.id)) {
+            if (!session.window.folded) {
+                chat_manager.mark_channel_as_seen(chat_manager.get_channel(session.id));
+            }
             chat_manager.get_messages({channel_id: session.id}).then(function (messages) {
                 session.window.render(messages);
                 if (scrollBottom) {
@@ -114,6 +124,14 @@ core.bus.on('web_client_ready', null, function () {
         });
     });
 
+    chat_manager.bus.on('update_channel_unread_counter', null, function (channel) {
+        _.each(chat_sessions, function (session) {
+            if (channel.id === session.id) {
+                session.window.update_unread(channel.unread_counter);
+            }
+        });
+    });
+
     chat_manager.is_ready.then(function() {
         _.each(chat_manager.get_channels(), function (channel) {
             if (channel.is_detached) {