A Gdk_Window, in gtk+, is really a GObject. That means it comes with reference counting. Changing this in GtkAda would break a lot of code though, so we only bind it as a C_Proxy, but provide Gdk.Window.Ref and Gdk.Window.Unref to access the reference counting support.
type Gdk_Cursor is new Glib.C_Proxy;
type Gdk_Visual is new Glib.C_Proxy;
type Gdk_Window is new Glib.C_Proxy;
type Gdk_Window_Attr is new Glib.C_Proxy;