diff --git a/addons/mail/mail_message_view.xml b/addons/mail/mail_message_view.xml
index 81b47db819a..6c15114cde6 100644
--- a/addons/mail/mail_message_view.xml
+++ b/addons/mail/mail_message_view.xml
@@ -115,7 +115,7 @@
             </field>
         </record>
         <record id="base.action_attachment" model="ir.actions.act_window">
-            <field name="view_mode">kanban,list,form</field>
+            <field name="view_mode">kanban,tree,form</field>
         </record>