mail-addons/res_partner_mails_count/templates.xml

<?xml version="1.0"?>
<openerp>
    <data>
        <record id="view_task_partner_info_form1" model="ir.ui.view">
            <field name="name">res.partner.mails.count</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_partner_form"/>
            <field name="priority" eval="50"/>
            <field name="groups_id" eval="[(4, ref('project.group_project_user'))]"/>
            <field name="arch" type="xml">
                <xpath expr="//div[@name='buttons']" position="inside">
                    <button class="oe_inline oe_stat_button" type="action"
                        name="%(action_mails_from)d"
                        context="{'search_default_partner_ids': [active_id]}"
                        icon="fa-envelope">
                        <field string="Mails from" name="mails_from" widget="statinfo"/>
                    </button>
	                <button class="oe_inline oe_stat_button" type="action"
                        name="%(action_mails_to)d"
                        context="{'search_default_author_id': active_id}"
                        icon="fa-envelope-o">
                        <field  string="Mails to" name="mails_to" widget="statinfo"/>
                    </button>
                </xpath>
            </field>
        </record>
    </data>
</openerp>