diff --git a/addons/mail/static/src/xml/activity.xml b/addons/mail/static/src/xml/activity.xml
index bd4a0fd044a..86d527b01ed 100644
--- a/addons/mail/static/src/xml/activity.xml
+++ b/addons/mail/static/src/xml/activity.xml
@@ -12,7 +12,7 @@
                 </small>
             </a>
         </div>
-        <div id="o_chatter_planned_activities" class="collapse in">
+        <div id="o_chatter_planned_activities" class="collapse in show">
             <t t-foreach="activities" t-as="activity">
                 <div class="o_thread_message" style="margin-bottom: 10px">
                     <div class="o_thread_message_sidebar">