diff --git a/addons/mail/static/src/xml/discuss.xml b/addons/mail/static/src/xml/discuss.xml
index f9921f8f9ad..744d624d564 100644
--- a/addons/mail/static/src/xml/discuss.xml
+++ b/addons/mail/static/src/xml/discuss.xml
@@ -133,7 +133,7 @@
     <t t-name="mail.chat.ControlButtons">
         <div>
             <button type="button" class="btn btn-primary btn-sm o_mail_chat_button_invite hidden-xs" title="Invite people">Invite</button>
-            <button type="button" class="btn btn-default btn-sm o_mail_chat_button_mark_read" title="Mark all as read">Mark all read</button>
+            <button type="button" class="btn btn-default btn-sm o_mail_chat_button_mark_read hidden-xs" title="Mark all as read">Mark all read</button>
             <button type="button" class="btn btn-default btn-sm o_mail_chat_button_unstar_all" title="Unstar all messages">Unstar all</button>
             <button type="button" class="btn btn-default btn-sm o_mail_chat_button_dm visible-xs" title="New Message">New Message</button>
             <button t-if="!disable_add_channel" type="button" class="btn btn-default btn-sm o_mail_chat_button_public o_mail_chat_button_private visible-xs" title="New Channel">New Channel</button>