Hi José,

>Thanks, this solution could be a solution for my framework, but I'm looking for a black box solution. I want a solution that it don´t force me to redefine my textbox class, I like to share this code with the fox community and this limitation is hard

I think the Paint event of the form fires when the current control changes. That's not on the container level, but maybe better than a timer.

In any case, I'd probably leave this in the responsibility of the user of my controls. That is, I'd add a method OnChangeFocus to my container and have them call this method in the textboxes. It's only a single line and should easily be added to the classes. Additionally you can offer a timer that does this automatically and a builder that adds the code to all elements in the container.

Christof