Question FPReport Variables - String concatenation and error on the variables screen

Hi Guys,

I am creating my first report.
When I do anything on the Variables form, I get an error message:
Operation Not Allowed On Sorted List.

The second issue, I want to concatenate the strings for the name of the person. I have FirstName, MiddleName and LastName.
I created a variable called FullName and I put in the expression, [fprDSPerson.FirstName] + ' ' + [fprDSPerson.MiddleName] + ' ' + [fprDSPerson.LastName].
It gives me an error and I can't find documentation about this anywhere.

Thanks,

Jose.

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