diff --git a/addons/im_livechat/static/src/js/im_livechat.js b/addons/im_livechat/static/src/js/im_livechat.js
index f29ea4ce79a..cbe5d27e3bd 100644
--- a/addons/im_livechat/static/src/js/im_livechat.js
+++ b/addons/im_livechat/static/src/js/im_livechat.js
@@ -143,7 +143,7 @@ var LivechatButton = Widget.extend({
             self.$el.hide();
         });
         this.chat_window.on("close_chat_session", this, function () {
-            var input_disabled = this.chat_window.$(".o_chat_input input").prop('disabled');
+            var input_disabled = this.chat_window.$(".o_chat_composer input").prop('disabled');
             var ask_fb = !input_disabled && _.find(this.messages, function (msg) {
                 return msg.id !== '_welcome';
             });
@@ -237,7 +237,7 @@ var LivechatButton = Widget.extend({
     },
 
     ask_feedback: function () {
-        this.chat_window.$(".o_chat_input input").prop('disabled', true);
+        this.chat_window.$(".o_chat_composer input").prop('disabled', true);
 
         var feedback = new Feedback(this, this.channel.uuid);
         feedback.replace(this.chat_window.thread.$el);
diff --git a/addons/mail/static/src/js/chat_window.js b/addons/mail/static/src/js/chat_window.js
index 9ffa0ed8c28..da8900b8230 100644
--- a/addons/mail/static/src/js/chat_window.js
+++ b/addons/mail/static/src/js/chat_window.js
@@ -16,9 +16,9 @@ var HEIGHT_FOLDED = '28px';
 return Widget.extend({
     template: "mail.ChatWindow",
     events: {
-        "click .o_chat_input": "focus_input", // focus even if jquery's blockUI is enabled
-        "keydown .o_chat_input": "on_keydown",
-        "keypress .o_chat_input": "on_keypress",
+        "click .o_chat_composer": "focus_input", // focus even if jquery's blockUI is enabled
+        "keydown .o_chat_composer": "on_keydown",
+        "keypress .o_chat_composer": "on_keypress",
         "click .o_chat_window_close": "on_click_close",
         "click .o_chat_title": "on_click_fold",
     },
@@ -40,7 +40,7 @@ return Widget.extend({
         this.is_hidden = false;
     },
     start: function () {
-        this.$input = this.$('.o_chat_input input');
+        this.$input = this.$('.o_composer_text_field');
         this.$header = this.$('.o_chat_header');
 
         this.thread = new ChatThread(this, {
diff --git a/addons/mail/static/src/js/composer.js b/addons/mail/static/src/js/composer.js
index dc90c2891e4..4da4bdf6774 100644
--- a/addons/mail/static/src/js/composer.js
+++ b/addons/mail/static/src/js/composer.js
@@ -494,7 +494,9 @@ var BasicComposer = Widget.extend({
             case $.ui.keyCode.ENTER:
             case $.ui.keyCode.UP:
             case $.ui.keyCode.DOWN:
-                this.mention_manager.proposition_navigation(event.which);
+                if (this.mention_manager.is_open()) {
+                    this.mention_manager.proposition_navigation(event.which);
+                }
                 break;
             // Otherwise, check if a mention is typed
             default:
diff --git a/addons/mail/static/src/js/extended_chat_window.js b/addons/mail/static/src/js/extended_chat_window.js
index 652a6236591..3a298b95a96 100644
--- a/addons/mail/static/src/js/extended_chat_window.js
+++ b/addons/mail/static/src/js/extended_chat_window.js
@@ -3,27 +3,44 @@ odoo.define('mail.ExtendedChatWindow', function (require) {
 
 var chat_manager = require('mail.chat_manager');
 var ChatWindow = require('mail.ChatWindow');
+var composer = require('mail.composer');
 
 return ChatWindow.extend({
     template: "mail.ExtendedChatWindow",
 
     start: function () {
         var self = this;
-        return this._super().then(function () {
-            if (self.options.thread_less) {
-                self.$el.addClass('o_thread_less');
-                self.$('.o_chat_search_input input')
-                    .autocomplete({
-                        source: function(request, response) {
-                            chat_manager.search_partner(request.term, 10).done(response);
-                        },
-                        select: function(event, ui) {
-                            self.trigger('open_dm_session', ui.item.id);
-                        },
-                    })
-                    .focus();
-            }
-        });
+        var def;
+        if (self.options.thread_less) {
+            this.$el.addClass('o_thread_less');
+            this.$('.o_chat_search_input input')
+                .autocomplete({
+                    source: function(request, response) {
+                        chat_manager.search_partner(request.term, 10).done(response);
+                    },
+                    select: function(event, ui) {
+                        self.trigger('open_dm_session', ui.item.id);
+                    },
+                })
+                .focus();
+        } else if (!self.options.input_less) {
+            var basic_composer = new composer.BasicComposer(self, {mention_partners_restricted: true});
+            basic_composer.on('post_message', self, function (message) {
+                this.trigger('post_message', message, this.channel_id);
+            });
+            basic_composer.once('input_focused', self, function () {
+                var channel = chat_manager.get_channel(this.channel_id);
+                var suggestions = chat_manager.get_mention_partner_suggestions(channel);
+                basic_composer.mention_set_prefetched_partners(suggestions);
+            });
+            def = basic_composer.replace(self.$('.o_chat_composer'));
+        }
+        return $.when(this._super(), def);
+    },
+    // Override on_keydown to only prevent jquery's blockUI to cancel event, but without sending
+    // the message on ENTER keydown as this is handled by the BasicComposer
+    on_keydown: function (event) {
+        event.stopPropagation();
     },
 });
 
diff --git a/addons/mail/static/src/js/window_manager.js b/addons/mail/static/src/js/window_manager.js
index eccafd08b0c..556e2f7b549 100644
--- a/addons/mail/static/src/js/window_manager.js
+++ b/addons/mail/static/src/js/window_manager.js
@@ -69,7 +69,6 @@ function open_chat (session, options) {
         });
 
         chat_session.window.on("post_message", null, function (message, channel_id) {
-            message.content = _.escape(message.content);
             chat_manager
                 .post_message(message, {channel_id: channel_id})
                 .then(function () {
@@ -117,7 +116,7 @@ function open_chat (session, options) {
                 }, 0); // setTimeout to prevent to execute handler on first scroll_to, which is asynchronous
                 if (options.passively) {
                     // mark first unread messages as seen when focusing the window, then on scroll to bottom as usual
-                    chat_session.window.$('.o_mail_thread, .o_chat_input').one('click', function () {
+                    chat_session.window.$('.o_mail_thread, .o_chat_composer').one('click', function () {
                         chat_manager.mark_channel_as_seen(session);
                     });
                 } else if (!display_state.chat_windows_hidden && !session.is_folded) {
diff --git a/addons/mail/static/src/less/chat_window.less b/addons/mail/static/src/less/chat_window.less
index 12d7ae3e682..3109a267913 100644
--- a/addons/mail/static/src/less/chat_window.less
+++ b/addons/mail/static/src/less/chat_window.less
@@ -77,7 +77,7 @@
         }
     }
 
-    .o_chat_input {
+    .o_chat_composer {
         .o-flex(0, 0, auto);
         > input {
             padding: 5px;
diff --git a/addons/mail/static/src/less/extended_chat_window.less b/addons/mail/static/src/less/extended_chat_window.less
index 68e58ffab12..99a308241eb 100644
--- a/addons/mail/static/src/less/extended_chat_window.less
+++ b/addons/mail/static/src/less/extended_chat_window.less
@@ -1,19 +1,34 @@
-.o_chat_window.o_thread_less {
-    .o_chat_search_input {
-        .o-flex-display();
-        padding: 5px;
-        > span {
-            .o-flex(0, 0, auto);
+.o_chat_window {
+    &.o_thread_less {
+        .o_chat_search_input {
+            .o-flex-display();
+            padding: 5px;
+            > span {
+                .o-flex(0, 0, auto);
+            }
+            > input {
+                margin-left: 5px;
+                .o-flex(1, 1, 100%);
+            }
         }
-        > input {
-            margin-left: 5px;
-            .o-flex(1, 1, 100%);
+        .o_mail_thread {
+            background-color: lightgray;
+        }
+        .o_chat_composer {
+            display: none;
         }
     }
-    .o_mail_thread {
-        background-color: lightgray;
-    }
-    .o_chat_input {
-        display: none;
+
+    .o_chat_composer {
+        .o_composer {
+            border-top: 1px solid lightgray;
+            .o_composer_input textarea {
+                display: block;
+                padding: 5px;
+            }
+        }
+        .o_composer_attachments_list, .o_composer_buttons {
+            display: none;
+        }
     }
 }
diff --git a/addons/mail/static/src/xml/chat_window.xml b/addons/mail/static/src/xml/chat_window.xml
index ef2d478b467..17a0a0166cc 100644
--- a/addons/mail/static/src/xml/chat_window.xml
+++ b/addons/mail/static/src/xml/chat_window.xml
@@ -12,8 +12,8 @@
             </div>
             <div class="o_chat_content">
             </div>
-            <div t-if='!widget.options.input_less' class="o_chat_input">
-                <input t-att-placeholder="widget.options.placeholder"/>
+            <div t-if='!widget.options.input_less' class="o_chat_composer">
+                <input class="o_composer_text_field" t-att-placeholder="widget.options.placeholder"/>
             </div>
         </div>
     </t>
diff --git a/addons/mail/static/src/xml/composer.xml b/addons/mail/static/src/xml/composer.xml
index 1c1f36499bb..a75708401ce 100644
--- a/addons/mail/static/src/xml/composer.xml
+++ b/addons/mail/static/src/xml/composer.xml
@@ -15,7 +15,7 @@
          </t>
          <div t-attf-class="o_composer #{widget.extended ? 'o_extended_composer' : ''}">
              <div class="o_composer_input">
-                 <textarea tabindex="2" placeholder="Write something..."/>
+                 <textarea class="o_composer_text_field" tabindex="2" placeholder="Write something..."/>
              </div>
              <t t-if="!widget.extended">
                  <div class="btn-group o_composer_buttons">