dSizer lays out your UI elements along a one-dimensional arrangement. As a result, their key property is Orientation, which can be either Horizontal or Vertical. Objects controlled by the sizer are sized and positioned according to the values set when they are added to the sizer.
Sizers can be nested within other sizers to create very complex layouts.
Sizers are not actual physical objects in the UI; rather, they are best thought of as hierarchical rules that govern the layout of forms in the UI. Controls are physically contained by the form in which they are created, and some controls, such as [dPanel]?, can contain other controls. Sizers are not a part of this containership. Rather, they are assigned to a container in order to govern how the object contained within are to be postioned and sized. When a container receives a Resize message, it tells its Sizer to re-caclulate the size and position of the items under its control to fit the new container size.