This call can only happen after the application has started;
typically, you should add new application windows in response
to the emission of the GApplication::activate signal.
This call is equivalent to setting the [property@Gtk.Window:application]
property of window to application.
Normally, the connection between the application and the window
will remain until the window is destroyed, but you can explicitly
remove it with [method@Gtk.Application.remove_window].
GTK will keep the application running as long as it has
any windows.
Adds a window to application.
This call can only happen after the application has started; typically, you should add new application windows in response to the emission of the GApplication::activate signal.
This call is equivalent to setting the [property@Gtk.Window:application] property of window to application.
Normally, the connection between the application and the window will remain until the window is destroyed, but you can explicitly remove it with [method@Gtk.Application.remove_window].
GTK will keep the application running as long as it has any windows.