David,
I thought so too but it had to be somewhere in Doug Hennig's code. But since he does not support his SFQuery any more, I have nobody to turn to.

>Dmitry,
>
>It sounds like somewhere later on there is code that is doing a SET CLASSLIB without the ADDITIVE clause, which will wipe out the one in your main.prg.
>
>>I have a class for calendar lookup, which is a container with textbox and a button. When button is clicked, calendar class is created and is popped up. The container and the calendar pop-up class reside in the same .vcx file (MYCLASSLIB.VCX). At the top of the application I
>>SET CLASSLIB TO MYCLASSLIB ADDITIVE where calendar classes reside. All works well.
>>
>>But I get error when using this container class in Stonefield Query (SFQuery). When user selects a date field for the filter, the calendar control is displayed. But when user clicks on calendar popup button, error "Class definition Calendar not found" appears. But if I add a line SET CLASSLIB TO MYCLASSLIB ADDITIVE in the click method of the button, before creating object of class Calendar, program works without the error.
>>
>>My question is, why within my program, the statement SET CLASSLIB TO MYCLASSLIB ADDITIVE is enough to allow Calendar object to be created. But when used from SFQUERY I have to repeat the statement again?