I added a Thingy to my site. Then, I created a Thing. In that Thing, I created a field. After creating the field (textarea) I needed to edit it. Upon editing the field, I could not save the change I made because there is no submit button (or cancel button for that matter). A screenshot is attached.

However, if I save the Thing, and then edit the Thing from the Manage Things screen, I can edit the field and save my changes.

version 7.7.12