xbus_envelope.xml

<?xml version="1.0" encoding="UTF-8" ?>
<odoo>
    <record id="xbus_envelope_view_tree" model="ir.ui.view">
        <field name="name">xbus_envelope_view_tree</field>
        <field name="model">xbus.envelope</field>
        <field name="arch" type="xml">
            <tree>
                <field name="create_date" />
                <field name="uid" />
                <field name="comment" />
                <field name="message_count" />
            </tree>
        </field>
    </record>

    <record id="xbus_envelope_view_form" model="ir.ui.view">
        <field name="name">xbus_envelope_view_form</field>
        <field name="model">xbus.envelope</field>
        <field name="arch" type="xml">
            <form string="Xbus Envelope">
                <sheet>
                    <div class="oe_button_box" name="button_box">
                        <button
                            class="oe_stat_button"
                            name="action_open_message"
                            type="object"
                            icon="fa-comments"
                        >
                            <field
                                name="message_count"
                                widget="statinfo"
                                string="Messages"
                            />
                        </button>
                    </div>
                    <group>
                        <field name="create_date" />
                        <field name="uid" />
                        <field name="comment" />
                    </group>
                    <group>
                        <field name="message_ids">
                            <tree>
                                <field name="uid" />
                                <field name="type" />
                            </tree>
                        </field>
                    </group>
                </sheet>
            </form>
        </field>
    </record>

    <record id="xbus_envelope_action" model="ir.actions.act_window">
        <field name="name">Xbus Envelopes</field>
        <field name="res_model">xbus.envelope</field>
        <field name="view_mode">tree,form</field>
    </record>

    <menuitem
        id="xbus_envelope_menuitem"
        name="Envelopes"
        parent="menu_xbus_common"
        action="xbus_envelope_action"
        sequence="1"
        groups="group_xbus_reader"
    />
</odoo>