> I put this code in Grid's Init method, but don't succeed :(

You need to set Sparse = .F. for the editbox column...

> Sorry, I didn't catch your idea. Could it be simple solution?

Well, not real complex, but some changes would be needed...you could use a View based on the table, set the grid source to the view. In the view, you could add 3 char fields to display the Y/N based on the logical field values...then when a Y/N was changed, you would update the corresponding logical field...not real simple, but that's one idea...