Context: it is possible to set the "Participants" property to a semicolumn separated list of participants. If you set the MaxParticipants to 1, I need to know what user did actually permformed the action. I noticed that the record.LastModifiedBy attribute is set to the WF systemuser and not to the user that performed the task.
Solution: There must be property "ActualParticipant" that contains the participant that performed the task in the current process instance.
Applies to: all ADAM blocks that are involving user interaction (EditMetaData, PickUsers etc).
Customer support service by UserEcho