public Window ()
Creates a new Window, which is a toplevel window that can contain other widgets.
To get an undecorated window (no window borders), use set_decorated.
All top-level windows created by Window are stored in an internal top-level window list. This list can be obtained from list_toplevels. Due to Gtk+ keeping a reference to the window internally, Window does not return a reference to the caller.
a new Window.