>Hi Peter,
>
>check out: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceinternational5/html/wce50lrfLCTYPEConstants.asp

Hi Christof,

I understand almost nothing of that page. But I think you're trying to tell me that it's a setting determined by the country chosen in Regional Settings.

I have still not found any place in my OS's where it is displayed explicitly.

I have found another interesting website: http://www.pjh2.de/datetime/weeknumber/wnc.php?l=en
(I advise people to also skip to higher pages on that site.) It gives a nice view on the diversity and also on which OS has implemented the scheme bad, better or good.

There are two settings important here:
1) What is the first day of the week.
2) How is the first week of year determined.

The seconds setting cannot always be determined without first determining the first setting.

My advice is:
Either offer only the ISO 8601 norm: FDOW is Monday, and FWOY is first week with a Thursday.
Or offer TWO listboxes. One listbox is used to determine FDOW, and the other listbox determines the FWOY algorithm.