Add 'Opportunity' field on a new 'CRM' notebook page on Calendar

base_mail_sender_bcc/__manifest__.py

@@ -17,5 +17,5 @@ With this module, when Odoo sends an outgoing email, it adds the sender as Bcc (
     'author': 'Akretion',
     'website': 'https://github.com/akretion/odoo-usability',
     'depends': ['base'],
-    'installable': False,
+    'installable': True,
 }

crm_usability/views/crm_lead.xml

@@ -19,4 +19,20 @@
     </field>
 </record>
 
+
+<!-- Add "Opportunity" field on calendar event -->
+<record id="view_calendar_event_form" model="ir.ui.view">
+    <field name="name">calendar.event.form.usability</field>
+    <field name="model">calendar.event</field>
+    <field name="inherit_id" ref="calendar.view_calendar_event_form"/>
+    <field name="arch" type="xml">
+        <xpath expr="//notebook" position="inside">
+            <page name="crm" string="CRM">
+                <group>
+                    <field name="opportunity_id" />
+                </group>
+            </page>
+        </xpath>
+    </field>
+</record>
 </odoo>