[fpc-devel] How to check why WideStringCompare fails?

[Martin]

It seems for some people using 2.7.1
     FCurrentString: string;

         if 0 = WideCompareText(UTF8Decode(fCurrentString),
                        UTF8Decode(Copy(ItemList[i], 1, 
Length(fCurrentString))))

does not compare correct.
http://bugs.freepascal.org/view.php?id=25156


How can they best check if this is:
- an issue with their setup, maybe widestringmanager failing.
- an issue with UTF8Decode
-- maybe because the encoding of FCurrentString?

Though I wonder which encoding FCurrentString could have an their 
system, to fail latin a-z letters from being correctly converted?