Event-type specific custom participant data fields are not loaded on backoffice participant form if the event is NOT a paid event

To recreate:

• add a custom data set for Participants > Any with a field
• add another custom data set for Participants (Event Type) > Workshop
• create a free event, type = Workshop
• use link to "Register Participant"

The pane for the first custom data set is shown. The "workshop" custom data set is never retrieved.

— original post ----
Shown here:
http://drupal.demo.civicrm.org/civicrm/participant/add?reset=1&action=add&context=standalone&eid=8

There is a custom field for participants called "Table" of event type "performance" that should be showing up for 'register participant' but it's not.
http://drupal.demo.civicrm.org/civicrm/admin/custom/group?reset=1

There is interest in getting this bug fixed in 4.1, sponsorship available.