> The texbox are : txlCPF, txlCGC, txlNuINPI. When the user selection is "F", I want to bring txlCPF to the front and so on.

Jose,

I think I understand the problem better now. I don't think you are having a problem with zorder since you are setting the enabled properties of the other textbox controls to false.

In your case logic, try calling the refresh method of the active textbox control. This.Parent.Parent.txlCPF.TextBox.Refresh(). I think since you have the controls stacked, the active control just needs to be repainted.

Kind Regards,

Mat