Your change seems to fix the problem, thanks a million. I hope it stays this way, because yesterday my change worked for a moment and then stopped working.

>>Hi everybody,
>>
>>I have the following code in the lAddBlank_Assign method (this is a custom property of the combobox):
>>
>

>LPARAMETERS vNewVal
>
>*To do: Modify this routine for the Assign method
>WITH THIS
>	IF m.vNewVal AND ASCAN(.aRowSource,SPACE(1),1,-1,1) = 0
>        	DIMENSION .aRowSource[ALEN(.aRowSource,1)+1, ALEN(.aRowSource,2) ] && add one more row
>		AINS(.aRowSource,1) && inserts a row
>		PRIVATE lnI
>                FOR lnI =1 TO ALEN(.aRowSource,2)
>   		    .aRowSource[m.lnI] = " "
>		NEXT
>                .aRowSource[2] = CAST(NULL AS C)  && NULL literal it is a Logical
>        ENDIF
>       .lAddBlank = m.vNewVal
>ENDWITH
>

>AND
>

>SET NULLDISPLAY TO "?"
>

>>
>>The code is executed. However, the value for that blank row is empty and not null. Does it mean, that the comobobox with the array as rowsource can not have a null value inserted? Should I try to replace myself the empty value with NULL? Do you have ideas what could be wrong?
>>
>>The original value is NULL in the table.
>
>NULL WITH DATATYPE = NULL OR NULL WITH A KNOWN DATATYPE :)
>>
>>Thanks a lot in advance.