[flexcoders] SummaryField summaryFunction question

[Eric Cancil]

When writing a summaryFunction for summaryFields I've noticed that if it
returns a string (let's say you want to format a summary to be a number
delimited by commas at the thousands, or add a dollar sign to a dollar
amount summary) the NaN is displayed in your summary row.  To me this really
doesn't make sense....Does anyone have ideas?