Custom fields for Participant for Event Type not appearing when Participant is registered for an event

A custom form (ie set of custom fields) for Participants for Event Type (eg Course) created in 4.4.6 and then upgraded to 4.5 beta 3 fails to appear when registering a Participant for an Event of type relevant type.
In 4.4.6 when registering a participant for an event of the relevant type the custom form would appear when the event (of the relevant type) had been selected.