The problem is caused by set udfparms to reference. See http://fox.wikis.com/wc.dll?Wiki~SetUDFParms~VFP why you shouldn't change this setting in first place.

>I downloaded the Common Controls Library v.3.9 (commctrl.zip)
>from UT downloads and ran the following code:
>
>

>setdatae()
>DO Form  frmdatetimepicker.scx
>
>proc SETDATAE
>set talk off
>SET DEVELOPMENT ON
>SET REPROCESS TO 30 SECONDS
>set notify on
>set strictdate to 1
>set sysformats on
>set hour to 24
>LOCAL ldDate, lcDate
>ldDate = {^2001-12-31}
>lcDate = DTOC(ldDate)
>DO CASE
>  CASE RIGHT(lcDate,IIF(SET("Century")='ON',4,2)) = ;
>	RIGHT(ALLTRIM(STR(YEAR(ldDate))),IIF(SET("Century")='ON',4,2)) ;
>			AND LEFT(lcDate,2) = ALLTRIM(STR(MONTH(ldDate)))
>		SET DATE MDY
>	
>  CASE RIGHT(lcDate,IIF(SET("Century")='ON',4,2)) = ;
>	RIGHT(ALLTRIM(STR(YEAR(ldDate))),IIF(SET("Century")='ON',4,2)) ;
>		AND LEFT(lcDate,2) = ALLTRIM(STR(DAY(ldDate)))
>		SET DATE DMY
>	
>  CASE LEFT(lcDate,IIF(SET("Century")='ON',4,2)) = ;
>	RIGHT(ALLTRIM(STR(YEAR(ldDate))),IIF(SET("Century")='ON',4,2)) ;
>			AND RIGHT(lcDate,2) = ALLTRIM(STR(DAY(ldDate)))
>		SET DATE YMD
>		
>  OTHERWISE && Not sure what to do, date format is not recognized
>
>  ENDCASE
>
>SET CENTURY ON         && must be after SET SYSFORMATS
>set excl off
>set escape off
>set print off
>set cons on
>set device to screen
>set step off
>set ansi on
>set autosave on
>set talk nowind
>set compatible foxplus
>set cpdialog off
>set status bar off
>set readborder on
>SET BELL OFF
>SET HEADING OFF
>SET MENU OFF
>SET SAFETY OFF
>set exact on
>set near on
>set deleted on
>set udfparms to reference
>return
>

>
>after that frmdatetimepicker form does not close: clicking to its upper
>right corner causes close button to become inactive. Close button inside
>form does not work also.
>
>Is it possible to use this class without changing the setdate()
>function. I do'nt want to change setdate() because my application requires those settings.