Hi Erel, thank you for your reply.
The main reason for my post is that I'd like to understand how it works the "delegation", in general.
From your post#2 I get that when we need to work on an event inside a B4xPage, we raise the event in Main and write the corresponding sub only on those pages that need to work on that event.
BTW, is it ok how I arranged for the Back key in my post#1? I verified that it works like I described, but a confirmation is always welcomed.