New formula field not listed as an Available Field in Sort Expert

Hi Guys,

CR2013 Support Pack 3.  I have added a new formula field, and need to add it to the Sort Criteria for my report.  However, it is not listed in the list of available fields.

I saved the report, closed and reopened it, and that did not help. 

Anyone know of criteria that would make a report field Not appear there?  ffRealAnalysis is defined and used in the report.  It is set in WhilePrintingRecords scope, maybe that is it?