Currently, we allow users with "administer CiviCRM" permissons (and with OR without "access all custom data" permission) to create and modify custom field groups and fields. However, when a user who does NOT have "access all custom data" permissions attempts to use a custom field for a Profile field - the custom fields are hidden (not included) in the field selector. This is inconsistent and confusing.
I think the "intent" of the "access custom data" permission is to control input/viewing to custom field data - AND if a person is creating or editing profile fields that means they have "administer CiviCRM" permission.
So... remove the filter on uf/group/field - field select form - that checks "access custom data" permission.