social/website_mail_snippet_table_edit/views/snippets.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- © 2016 Antiun Ingeniería S.L. - Jairo Llopis
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html). -->

<openerp>
<data>

    <template id="email_designer_snippets"
              inherit_id="website_mail.email_designer_snippets">
        <xpath expr="//div[@id='snippet_options']">
            <div data-snippet-option-id='tr_editor'
                 data-selector-children="[data-oe-field='body_html'] tbody, [data-oe-field='body_html'] thead, [data-oe-field='body_html'] tfoot"
                 data-selector="[data-oe-field='body_html'] tr"/>
        </xpath>
    </template>

</data>
</openerp>