Hi Nick,
Thanks for the suggestion. Actually I was thinking about that.
In my case I definitely need a top level form as a main form in my application (because I need the resize event which I don't have in _SCREEN). I haven't managed to keep visible, (on top of my main form) a modeless form, I think it's impossible, even in case of a formset. That's why I can't proceed in this way, using another form.
Thanks again!