Thanks and as I use KeyPress I can capture the keystroke and replace with a null.

I have also put up a thread about validations through tables for critical analysis, if you are interested will you go through it for me.

Thanks a lot.

>From VFP help :
>"Also, CTRL+0 is supported in ON KEY LABEL in Visual FoxPro, allowing you to redefine the key combination used to enter a null value into a field."
>
>"Using NULL in Values and Expressions
>In Visual FoxPro, you assign the null value programmatically with the .NULL. token or interactively with CTRL+0 in a field. "
>
>Cetin
>
>
>>Thanks I just tried it and in my auto complete combo where I replace the ID as soon as I keypress, failed but this is any idea I will work on as it is, I hope, default VFP behaviour.
>>
>>>>Hi all
>>>>
>>>>I have this form with a cbo. This cbo is allowed to remain empty. If the user moves forward without modifying then alls well.
>>>>
>>>>Now supposing the user makes a selection and then he doesn't want it, how can he undo his selection. This cbo is connected to a lookup master database, as soon as the selection is made the FK in this table is updated with the PK from the lookup master.
>>>>
>>>>Except reverting changes is there any solution. Please advise.
>>>
>>>As an addition to Alex and David, Ctrl+0 'zero' unselects.
>>>Cetin