<?xml version="1.0"?>
<field name="model" position="after">
                <filter string="Mail Thread" name="is_mail_thread" domain="[('is_mail_thread', '=', True)]"/>
                <filter string="Mail Activity" name="is_mail_activity" domain="[('is_mail_activity', '=', True)]"/>
                <filter string="Mail Blacklist" name="is_mail_blacklist" domain="[('is_mail_blacklist', '=', True)]"/>
            </field>
        