BPMN2 Diagram Editor for JBDS 7.x does not allow entering comma "," for adding multiple group id in "Group Id" property

Issue

• There is an issue with using Group Id attribute of User Task in BPMN2 Diagram Editor of JBDS 7 . The user can't input comma(",") in User Task -> Attributes -> Group Id text field.
• Although BPMS User Guide [1] narrates that it is possible to specify multiple Group Id separated by "," , but it seems the JBDS designer is not allowing to do so.

GroupID
    comma-separated list of groups who are entitled to perform the generated User Task 

• Is this a bug? Is there any workaround on this?

[1] A.11.5. User Task