Multi Instance Process and Nodes - Expression Editor for Selector

Please add an expression editor on "MI Collection input" to allow for non-root level lists to be used.

This enhancement request is for both:

• Multi-instance sub procedures, and
• Multi-instance task nodes

The current workaround is to define another process variable, and then assign the collection to iterate in a prior script task. However this creates duplicate data (in the case and in the process), and is a very inefficient method of what should be a simple modeling task:

 
com.myspace.ams_pilot.Workflow currentWorkflow = (com.myspace.ams_pilot.Workflow) caseFile_Workflow;
kcontext.setVariable( "Stages", currentWorkflow.getStages() );
}}

Acceptance criteria

TODO