VC 6.0 CComboBoxEx Sorting

I am using my own class derived from the CComboBoxEx class in Visual C++ 6.0, and the items I insert into it are not sorted.

When I look at my .rc file, CBS_SORT is listed as part of the style.

Any clues on how to get it to sort?

I'm developing on Windows NT 4.0.

Thanks!