All container controls can have a Sizer class associated with them; this Sizer can be used to control the layout of the direct children of the control that the Sizer belongs to. There are several types of Sizer, each one providing slightly different capabilities and features to control the placement and sizing of the controls they manage; however, they all work on the same two-dimensional rectangle-based plane.
Among the available choices for Sizers, BoxSizer is the most basic, but it provides a simple and powerful way to control the layout of controls. This Sizer operates in one of two modes. It can lay out controls in either a single rectangular column or a row. Sizers can then be nested inside each other to create more complex layouts. In this recipe, we will explore some of the basics of using BoxSizer to layout controls on a panel.