<?xml version="1.0"?>
<calendar date_start="calendar_date" string="Mailings" hide_time="true" mode="month" color="state" quick_add="False">
                    <field name="mailing_model_id" string="Recipient" options="{'no_open': True}"/>
                    <field name="user_id" filters="1" invisible="1"/>
                    <field name="state" filters="1" invisible="1"/>
                </calendar>
            