Login / Register : add extended fields inside containers

Hello
Is there a way to add extended fields with Register inside containers?

I tried :

<input type="hidden" name="userextra.test" value="ok" />

but this is converted to a “root” extended field “userextra_test”

Try

<input type="hidden" name="userextra[test]" value="ok" />

If that doesn’t work, you probably have to write a custom hook.

Perfect, no need to write a custom hook !