social/mail_full_expand/views/mail_full_expand.xml

<?xml version="1.0" encoding="utf-8"?>

<!-- © 2014-2015 Grupo ESOC <http://www.grupoesoc.es>
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html). -->

<openerp>
<data>

<record id="view" model="ir.ui.view">
    <field name="name">mail.message.full_expand</field>
    <field name="model">mail.message</field>
    <field name="arch" type="xml">
        <form string="Message" version="7.0">
            <group>
                <field name="author_id" readonly="1"/>
                <field name="email_from" readonly="1"/>
                <field name="date" readonly="1"/>
                <field name="partner_ids"
                       widget="many2many_tags"
                       readonly="1"/>
                <field name="notified_partner_ids"
                       widget="many2many_tags"
                       readonly="1"/>
            </group>
            <h1><field name="subject" readonly="1"/></h1>
            <field name="body" readonly="1"/>
            <field name="attachment_ids"
                   widget="many2many_binary"
                   readonly="1"/>
        </form>
    </field>
</record>

<record id="act_window" model="ir.actions.act_window">
    <field name="name">Read Full Email</field>
    <field name="res_model">mail.message</field>
    <field name="src_model">mail.message</field>
    <field name="type">ir.actions.act_window</field>
    <field name="view_id" ref="view"/>
    <field name="view_type">form</field>
    <field name="view_mode">form</field>
    <field name="target">new</field>
</record>

</data>
</openerp>