Hi,
I just started using Joget workflow using step by step tutorial provided in this website. I've been following all the steps until I stuck at mapping process participants.
_http://dev.joget.org/community/display/KB/Map+the+Process+Participants._
I click Map Participant to users and click at add/edit mapping button. Refer image below: 
Then i click at map to user and group, but nothing happen. It seems error upon clicking that. please help. 