social/mail_sendgrid/views/sendgrid_email_view.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <!-- Extension of mail.mail form view -->
    <record model="ir.ui.view" id="email_form_view">
        <field name="name">mail.mail.sendgrid</field>
        <field name="model">mail.mail</field>
        <field name="inherit_id" ref="mail.view_mail_form"/>
        <field name="arch" type="xml">
            <button name="send" position="replace">
                <field name="send_method" invisible="1"/>
                <button name="send" string="Send Now" type="object" class="oe_highlight" attrs="{'invisible': ['|', ('send_method', 'not in', ['sendgrid','traditional']), ('state', '!=', 'outgoing')]}"/>
                <button name="send_sendgrid" string="Send (SendGrid)" type="object" class="oe_highlight" attrs="{'invisible': ['|', ('send_method', '=', 'sendgrid'), ('state', '!=', 'outgoing')]}"/>
            </button>
            <field name="body_html" position="attributes">
                <attribute name="widget">html</attribute>
            </field>
            <xpath expr="//field[@name='attachment_ids']/ancestor::page" position="after">
                <page string="SendGrid">
                    <group>
                        <field name="sendgrid_template_id"/>
                        <field name="sent_date" readonly="1"/>
                        <field name="opened" readonly="1"/>
                        <field name="click_count" readonly="1"/>
                        <field name="body_text"/>
                    </group>
                    <field name="substitution_ids" widget="one2many_list"/>
                    <field name="tracking_event_ids">
                        <tree default_order="time desc">
                            <field name="tracking_email_id"/>
                            <field name="time"/>
                            <field name="event_type"/>
                            <field name="url"/>
                        </tree>
                    </field>
                </page>
            </xpath>
        </field>
    </record>

    <!-- Extension of mail.mail tree view -->
    <record model="ir.ui.view" id="sendgrid_email_tree_view">
        <field name="name">mail.mail.sendgrid.tree</field>
        <field name="model">mail.mail</field>
        <field name="inherit_id" ref="mail.view_mail_tree"/>
        <field name="arch" type="xml">
            <field name="date" position="after">
                <field name="opened"/>
                <field name="click_count"/>
            </field>
        </field>
    </record>

    <!-- Extension of mail.mail search view -->
    <record model="ir.ui.view" id="sendgrid_email_search_view">
        <field name="name">mail.mail.sendgrid.search</field>
        <field name="model">mail.mail</field>
        <field name="inherit_id" ref="mail.view_mail_search"/>
        <field name="arch" type="xml">
            <xpath expr="//filter[@name='received']" position="after">
                <filter name="opened" string="Opened" domain="[('opened','=',True)]"/>
                <filter name="clicked" string="Clicked" domain="[('click_count','>',0)]"/>
            </xpath>
        </field>
    </record>

    <!-- Substitution line view -->
    <record id="view_sendgrid_substitution_line_tree" model="ir.ui.view">
        <field name="name">sendgrid.substitution.tree</field>
        <field name="model">sendgrid.substitution</field>
        <field name="arch" type="xml">
            <tree string="Template substitutions" editable="bottom">
                <field name="key"/>
                <field name="value"/>
            </tree>
        </field>
    </record>
</odoo>