ProcessContext BO not available

Jennifer Methlie

I'm setting up a process with a subprocess and want the sub-process' form to access the parent folder.   When I try  to change the parameter of the "other business object" to ProcessContext.FolderParent, it doesn't recognize it.  Instead it keeps wanting to change "FolderParent" to "Equals" or "ReferenceEquals".      The BusinessObject icon on the Expression Builder is also greyed out. 

 

What's going on?    Thanks