I have extended model mail.message using mechanizm of inheritance. Extended model has additional columns with types many2one and char.

Now I want to change template of mail.thread.message to make new columns be displayed in message.thread.

<?xml version="1.0" encoding="UTF-8"?>
<templates xml:space="preserve">
    <t t-extend="mail.thread.message">
        <t t-jquery="div.oe_mail-placeholder" t-operation="after">

         <div>NEW COLUMN #1</div>

         <div>NEW COLUMN #2</div>

       </t>
    </t>
</templates>

 How can I change context for rendering tempate, add new columns to it and display new columns?