diff --git a/addons/base_calendar/base_calendar_view.xml b/addons/base_calendar/base_calendar_view.xml
index d33f453c662..76a69c06759 100644
--- a/addons/base_calendar/base_calendar_view.xml
+++ b/addons/base_calendar/base_calendar_view.xml
@@ -270,7 +270,7 @@
                             icon="terp-partner" type="action"
                             context="{'model' : 'calendar.event', 'attendee_field':'attendee_ids'}" colspan="2"/>
                         <field name="attendee_ids" colspan="4"
-                            nolabel="1" widget="one2many" mode="tree,form">
+                            nolabel="1" widget="one2many" mode="tree">
                             <tree string="Invitation details" editable="top">
                                 <field name="sent_by_uid" string="From"/>
                                 <field name="user_id" string="To"/>