Empty comment boxes

[silvioricardoc]

1. Upload a new file and open it
2. Click any word
3. Add a label (e.g. ID in the MWE experiments)
4. Click [+] Add Comment
5. Click OK (it will fail)
6. Reload the page, and we see that step (5) actually succeeded
7. Click the same word as in (2)
8. Try to add an empty label (to delete the annotation) -- this fails

There is no way to delete a comment box, and after step (8), even adding text to the comment box does not work anymore.