We are currently on Cuba Version 6.7.8 but will soon be rolling over to the latest 6.8 release.
I duplicated your sample within our application and the setCaption() call from within the listener does not appear to have any effect on the record. Calling setCaption() alone in the init method without placing it in the listener does work but again this does not accomplish what we are looking for.
If you are seeing this work in 6.8 I will test this again once we’ve updated to the latest platform version.
Thank you for your response,