A Gtk_Vbutton_Box is a specific Gtk_Button_Box that organizes its
children vertically.
The beginning of the box (when you add children with Gtk.Box.Pack_Start)
is on the top of the box. Its end (for Gtk.Box.Pack_End) is on the bottom.
Types
type Gtk_Vbutton_Box isaccessall Gtk_Vbutton_Box_Record'Class;