diff --git a/addons/mail/static/src/js/chat_manager.js b/addons/mail/static/src/js/chat_manager.js
index 82299475db1..f425a4718f9 100644
--- a/addons/mail/static/src/js/chat_manager.js
+++ b/addons/mail/static/src/js/chat_manager.js
@@ -791,7 +791,7 @@ var chat_manager = {
                         }));
                     });
 
-                    return [members].concat(suggestions);
+                    return [members];
                 });
         }
         return channel.members_deferred;
diff --git a/addons/mail/static/src/js/client_action.js b/addons/mail/static/src/js/client_action.js
index e091590faa1..82b36f3425d 100644
--- a/addons/mail/static/src/js/client_action.js
+++ b/addons/mail/static/src/js/client_action.js
@@ -171,8 +171,8 @@ var ChatAction = Widget.extend(ControlPanelMixin, {
         this.searchview = new SearchView(this, dataset, view_id, {}, options);
         this.searchview.on('search_data', this, this.on_search);
 
-        this.basic_composer = new composer.BasicComposer(this);
-        this.extended_composer = new composer.ExtendedComposer(this);
+        this.basic_composer = new composer.BasicComposer(this, {mention_partners_restricted: true});
+        this.extended_composer = new composer.ExtendedComposer(this, {mention_partners_restricted: true});
         this.thread = new ChatThread(this, {
             display_help: true,
             shorten_messages: false,
diff --git a/addons/mail/static/src/js/composer.js b/addons/mail/static/src/js/composer.js
index dae8cdc4241..5d6de2bad50 100644
--- a/addons/mail/static/src/js/composer.js
+++ b/addons/mail/static/src/js/composer.js
@@ -331,6 +331,7 @@ var BasicComposer = Widget.extend({
             input_max_height: 150,
             input_min_height: 28,
             mention_fetch_limit: 8,
+            mention_partners_restricted: false, // set to true to only suggest prefetched partners
             send_text: _('Send'),
         });
         this.context = this.options.context;
@@ -620,7 +621,7 @@ var BasicComposer = Widget.extend({
                     }
                 }
             });
-            if (!suggestions.length) {
+            if (!suggestions.length && !self.options.mention_partners_restricted) {
                 // no result found among prefetched partners, fetch other suggestions
                 var kwargs = {
                     limit: limit,