Windows "piling up"

Hi everyone,

so i have this problem with Windows that sort of pile up. Let me explain better: i have an application with the same exact navigation structure as the dashboard shown on this site, and i use a guava eventbus to send event.
So what happens is this: i have a button in one page that does a procedure, and if it completes correctly it fires up an event. I also have a method registered to that event that show my window (that extends the regular window class). The window i show is a private class member, and i show it like this:
 

if (window == null) {
            window = new VatFoundClientiWindow("Partita iva individuata", vatFoundEvent.getFoundVat());
        } else {
            UI.getCurrent().removeWindow(window);
            window = new VatFoundClientiWindow("Partita iva individuata", vatFoundEvent.getFoundVat());
        }

Now, i have 3-4 views that uses this paradigm, BUT they use different events. What happens is this:
1 - I open the window on page A;
2 - I open the window on page B (after navigating there);
3 - I go again to page A and open a window, BUT this time two show instead of one;
4- I go to B again, same procedure, three windows.

And so on. That's why i say that they are piling up, it looks like they remain orphan and get shown.

How could i solve this?

Thanks a lot! 

Are you sure each page is not getting the same event, so they all create a window ?
In the code snippet you gave, is the window variable global or local ?

Well, i'm reasonably sure :D I'd like to check to be 100% sure, is there a way of using the debugger to follow the event specifically?
 

Probably... but you can also do it quite easily showing some event / windows reference (for instance in title)

Ok, so after some more intense debugging i found out that there are "ghost" instances that keep their listeners active and responde to the call...
I say "ghost" because i have a navigator / view paradigm exactly like the dashboard one, but all my views are stateless and cacheless.
So they should allegedly be destroyed and recreated after i change page. I have evidence of the recreation part since when i follow with the debugger the constructor is invoked, but it's like the garbace collector then doesn't collect past views.

Make any sense?