Activity History >> View Details for an Event Registration (participant) has the following behavior currently:
1. Initial screen (url below) is ok, but missing Source and Fee Level.
2. When you click Done button - the participant detail page is loaded AGAIN, but additional fields are shown (Event Source and Event Fee Level).
URL changes to: http://sandbox.devel.civicrm.org/civicrm/contact/view/participant
- View Details should give you screen with all fields (including source and fee level).
- Done button should take you back to Activities Tab -> Activity History selector (selectedChild=activity&history=1)