Nadya

Your code did not generate an error, but mine did. There are a number of strange things about your posted code. One unusual thing is lnSelect is not the work area for X, but for Y. It seems the replace command is switching aliases. Therefore, using select() and recno() is dangerous within this UDF. Its my preference to pass important data to the function instead of letting the function determine things on its own.

Did you try my code? BTW, I added some comments to the MatXTab wiki page. Please add any comments there when you get a chance.

Thanks!