Buenos dias Alejandro,
As far as I know, lists objects (and some others components) requires authentication mode (2nd radio button checked/Extranet) in order to use Login/credentials with operators mode.
For anonymous webApp, you must use webApp page (v6) activity, and it is completely different development method of course, but it works fine of course.
So, it depends on your needs; do you need an authenticated or anonymous webApp?
Regards
J-Serge