Right now, trainer can edit old text and send new text using the editable textarea in the bottom. However, sending the editable textarea content empty is not possible. What if we want to start again removing all text? We want to implemente this possibility with a dialog confirm element to warn the user that all text is going to be removed if he clicks "yes". Of course, the confirm element should not be displayed any time we edit the text, but only when we try to send all the content empty.