Activiti User task candidate groups property field deletion not happening

Question

I have created a new process diagram and it contains a user task. I have written properties for the user task, and mentioned a candidate group value.

Activiti user guide

Now i an trying to delete that value for the candidate groups field but i am not able to do that. Every time i changed that and saved, it not reflecting the deletion next time i open it.

I have to delete the process diagram every time an create a new one.

Updated : To give examples i have to add couple of images, because it's all about diagram as per activiti BPMN process is concerned.

And i have added the properties of EmployeeTask as shown :

Answer 1

I tried many a times but failed to do so, then i wrote to a person from Activiti group regading the issue. He told its a bug in this version of Activiti i.e Activiti 5.12 and they are going to fix this "bug" in the next release. To give the exact details they have already resolved the JIRA task that i had raised.

Lets wait for next release to get this issue resolved.