Allow Gtk::manage() for windows
Submitted by Daniel Elstner
Link to original bug (#787842)
Description
Now with the advent for Gtk::Application and its container-like behavior for top-level windows, I think it would make a lot of sense to allow Gtk::manage() to be allowed on Gtk::Window, like this:
app->add_window(*Gtk::manage(new MyAppWindow{}));
The current gtkmm-specific magic in Gtk::Application appears to recreate the old gtkmm2 pattern of Gtk::Main::run(window). Which is fine I guess, but it requires always creating the window even if it doesn't end up being used.
I think treating Gtk::Application like a container for top-level windows would reduce the friction between GTK+ and gtkmm design patterns somewhat.