diff --git a/app/models/communication/website/agenda/event.rb b/app/models/communication/website/agenda/event.rb
index af934528cd7d077791ca8f46193e140943693ea1..dbe10a7f0fddb6f442c53eb594dc52feaeedb5d2 100644
--- a/app/models/communication/website/agenda/event.rb
+++ b/app/models/communication/website/agenda/event.rb
@@ -50,6 +50,7 @@ class Communication::Website::Agenda::Event < ApplicationRecord
   include WithPermalink
   include WithSlug
   include WithTranslations
+  include WithTree
   include WithUniversity
 
   belongs_to  :parent,