diff --git a/runbot/models/build_error.py b/runbot/models/build_error.py
index 7d878c4e..dcd4ec94 100644
--- a/runbot/models/build_error.py
+++ b/runbot/models/build_error.py
@@ -18,7 +18,7 @@ class BuildError(models.Model):
     _name = "runbot.build.error"
     _description = "Build error"
 
-    _inherit = "mail.thread"
+    _inherit = ['mail.thread', 'mail.activity.mixin']
     _rec_name = "id"
 
     content = fields.Text('Error message', required=True)
diff --git a/runbot/views/build_error_views.xml b/runbot/views/build_error_views.xml
index 6a110906..b75ae4ce 100644
--- a/runbot/views/build_error_views.xml
+++ b/runbot/views/build_error_views.xml
@@ -94,6 +94,7 @@
             <div class="oe_chatter">
                 <field name="message_follower_ids" widget="mail_followers"/>
                 <field name="message_ids" widget="mail_thread"/>
+                <field name="activity_ids" widget="mail_activity"/>
             </div>
           </form>
         </field>