Hi Fabio

>The mistake always in thinking that there is something of coherent in the operation of VFP.

Yep - it's a dangerous assumption all right.

>Is possible write a arbitrary word, like "pippo", on RecordSource, but if you build "pippo" after, and refresh the grid, the grid go on blank mode;

Yes, exactly! But until you do the Refresh() it is perfectly acceptable to VFP which is why we need the additional checks.

>if you use
>grid.RecordSource=grid.RecordSource, the cursor is loaded.
>
>This is another bug.

Hmmm! Not sure I would call it a "bug" though. If you (as the developer) specify an invalid recordsource it is really your own responsibility. I mean that it is not really any different than setting the controlsource of (say) a Textbox to a non-existent table - VFP just throws an error there too.