I'm having the same issue mate. Works at preview stage, but not in tasks. Looking into how the new form builder can handle validations/events.
I have the same problem. I created a new project and a new process interface KIE WORKBENCH and I imported a file .bpmn created by Eclipse. This file contains a script that prints a message. When booted from Eclipse works correctly, but when I start the interface by running the process but not the message.
I also tried from the "Administration" to copy all the code in the java file present in the web interface but nothing. Someone knows how to solve this problem?
You must use "Grapfical Modeler", click "Form properties", check "Custom" and click "Save". Designer generate html. If you put java script then perform nicely.