posted 9 years ago
It doesn't really matter if you reuse the same window or create a new one, the behavior is just a personal styling decision for your application.
If it were me, I would favor using an existing window (e.g. menu displays in a window and is replaced by the game content in the same window).
The reason for this is that people are quite used to a browser based model which is very flat and a self-contained with internal navigation and no pop-up windows, so stick with that simplistic design wherever possible and it will likely be more familiar for your users.
Additionally if you port your application to mobile devices, they usually run pretty simplistic OSes and don't have popups and multiple windows, so sticking with one window for the entire application will make it easier to port your app.