Another Question About Custom Fields
 

I figure that since most users will eventually fill out their user profile after registering with the forum, why not make all those fields plus a custom one required before registration. However, I can not for the life of me figure out the combination of settings to make the fields required for registration only and just for new users. I don't want all users currently registered with my forum to answer the custom field question and I don't want registered users to have to answer the question to edit their profile. So out of all the required choices, how come I can't just select Yes, Registration only for Required.