Creates a new Window, which is a toplevel window that can contain other widgets.
Nearly always, the type of the window should be TOPLEVEL. If you’re implementing something like a popup menu from scratch (which is a bad idea, just use Menu), you might use POPUP. POPUP is not for dialogs, though in some other toolkits dialogs are called “popups”. In GTK+, POPUP means a pop-up menu or pop-up tooltip. On X11, popup windows are not controlled by the window manager.
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.
type of window
a new Window.