social/mail_follower_custom_notification/wizards/mail_subtype_assign_custom_notifications.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
    <data>
        <record id="view_mail_subtype_assign_custom_notifications" model="ir.ui.view">
            <field name="model">mail.subtype.assign.custom.notifications</field>
            <field name="arch" type="xml">
                <form>
                    <group>
                        <field name="subtype_ids" widget="many2many_tags" />
                    </group>
                    <footer>
                        <button type="object" name="button_apply" string="Apply"
                            class="oe_highlight" />
                        or
                        <button type="special" special="cancel" string="Cancel"
                            class="oe_link" />
                    </footer>
                </form>
            </field>
        </record>
        <act_window id="action_mail_subtype_assign_custom_notifications"
            name="Update existing subscriptions"
            src_model="mail.message.subtype"
            res_model="mail.subtype.assign.custom.notifications"
            view_id="view_mail_subtype_assign_custom_notifications"
            multi="False"
            key2="client_action_multi"
            target="new" />
    </data>
</openerp>