*I can not see the wrongs words underline on MF 57. I mean on the text boxes not in the app itself. Is that a bug?
*What does exactly auto check, it does not seem to have an impact on the text box.
I assume you're talking about the browser add-on? It doesn't support underlining errors yet. Auto-check means that the icon will show a green check mark if no errors are found or the number of potential errors:
Yep. Ok to the first. The second thing I found out what it did after posting. So ty.