Following the new editor's merge at https://github.com/odoo/odoo/pull/29775, the classes 'o_mail_wrapper' and 'o_mail_wrapper_td' were renamed to 'o_mailWrapper' and 'o_mailWrapper_td' because of what appears to be a JS-variable-search-replace fail. Strange enough, the scss was not impacted which allowed to see the bug in master. closes odoo/odoo#30544