The Application and ApplicationWindow Classes
A new set of classes were introduced in GTK+ 3.x: Gtk.Application and Gtk.ApplicationWindow. These classes are designed to be the base instances for your GUI application. They wrap the application and the main window behavior of your application. They have many built-in features and provide containers for the functions in your application. The Gtk.Application and Gtk.ApplicationWindow classes are described in detail in this chapter because they are the basis for all the example programs in this book.