A Box is a rectangular area organized into either a single row or a single column of child widgets, depending upon whether the box is horizontally or vertically oriented, respectively.

A Box is abstract - specific layout containers are provided in its sub classes, including a horizontal box, (Gtk.HBox), a vertical box (Gtk.VBox), and button boxes, (Gtk.ButtonBox).

Widgets that are 'packed' into a box are considered to be the children of the box, and the box controls their layout. Properties such as . control the layout of all the children in the box, whereas specific packing settings can be applied to each child individually, such as .(Widget, bool, bool, uint, PackType).