diff --git a/addons/event/event_view.xml b/addons/event/event_view.xml
index 8efae21f676..3125e03bea6 100644
--- a/addons/event/event_view.xml
+++ b/addons/event/event_view.xml
@@ -395,7 +395,7 @@
                             </group>
                             <group>
                                 <field name="nb_register"/>
-                                <field name="user_id" attrs="{'readonly':[('state','!=', 'draft')]}"/>
+                                <field name="user_id" attrs="{'readonly':[('state','!=', 'draft')]}" context="{'default_groups_ref': ['base.group_user', 'event.group_event_manager']}"/>
                             </group>
                             <group groups="base.group_no_one">
                                 <field name="create_date"/>