odoo/addons/mail/mail_thread_view.xml

<?xml version="1.0"?>
<openerp>
    <data>
        <record model="ir.ui.view" id="view_mailgate_thread_form">
            <field name="name">mail.thread.form</field>
            <field name="model">mail.thread</field>
            <field name="type">form</field>
            <field name="arch" type="xml">
                <form string="Email Thread">
                    <separator string="Communication History" colspan="4"/>
                    <field name="message_ids" nolabel="1" colspan="4" mode="tree">
                        <tree string="Communication History">
                            <field name="display_text"/>
                        </tree>
                    </field>
                    <field name="message_ids_social" colspan="4" widget="ThreadView"/>
                </form>
            </field>
        </record>

        <record model="ir.ui.view" id="view_mailgate_thread_tree">
            <field name="name">mail.thread.tree</field>
            <field name="model">mail.thread</field>
            <field name="type">tree</field>
            <field name="arch" type="xml">
                <tree string="Email Threads">
                    <field name="message_ids" />
                </tree>
            </field>
        </record>

         <!-- Emails thread action -->
        <record model="ir.actions.act_window" id="action_view_mailgate_thread">
            <field name="name">Email Threads</field>
            <field name="res_model">mail.thread</field>
            <field name="view_mode">tree,form</field>
            <field name="view_type">form</field>
            <field name="view_id" ref="view_mailgate_thread_tree"/>
        </record>
        <record model="ir.actions.act_window.view" id="action_view_mailgate_thread_view1">
            <field name="sequence" eval="1"/>
            <field name="view_mode">tree</field>
            <field name="view_id" ref="view_mailgate_thread_tree"/>
            <field name="act_window_id" ref="action_view_mailgate_thread"/>
        </record>
        <record model="ir.actions.act_window.view" id="action_view_mailgate_thread_view2">
            <field name="sequence" eval="2"/>
            <field name="view_mode">form</field>
            <field name="view_id" ref="view_mailgate_thread_form"/>
            <field name="act_window_id" ref="action_view_mailgate_thread"/>
        </record>

        <act_window
            context="{}"
            domain="[('res_model', '=', active_model), ('res_id', '=', active_id)]"
            id="act_thread_see_followers"
            name="See followers"
            res_model="mail.subscription"
            src_model="mail.thread"
            view_mode="tree,form"
            view_type="form"/>
    
    </data>
</openerp>