The attribute _mail_post_access='read' on a model allows user with read only access on the model to post a message. It was not taken into account on the client side, making the send message button disabled for user with readonly access on such model. This commit fixes this issue and now correctly takes into account that class parameter. Task-3178885 (Mail: fix 'readonly' post support) X-original-commit: odoo/odoo@d2b8612cf7 Part-of: odoo/odoo#114511