Andreas,
Seems like this maybe related to international character code support (judging by the differences in the sorting)? Not sure where QT port stands on this...
The same directory shows up in CMD using the builtin DIR command compared to some file managers:
CMD FileCommander/2
dir 2.20 2.40
-------------------------------
Anders Anders Änderung
AnderW Änderung Anders
PROG AnderW AnderW
PROG.01 PROG PROG
PROG.1 PROG.01 PROG.01
Änderung PROG.1 PROG.1
Even old OS/2 1.2 PM applications can sort correctly. Without PM only FC/2 Version 2.20 can be trusted, later versions have a strange behaviour and should for security reasons not be used in critical situations.
But why in Qt "file.1" is ranking higher than "file"? No NLS stuff should be affected.