Portion.FontIndex returning -1

When I try to get the FontIndex of a portion of text, it always returns -1. Is this a code for a default value, or just an error…?

Dear mrand01,

Please read again my previous post about that.
https://forum.aspose.com/t/111038

Dear mrand01,

Oh, I’m sorry. FontIndex??? Yes, it’s default value.
Real value of such font can be found on MainMaster only in the same frame.
Automatic calculating default fonts will be implemented soon.