HBox and VBox - layouting
HBox and VBox containers lay out the containers nested within them.
The child containers are layed out either horizontally from left to right (HBox) or vertically from top to bottom (VBox).
Containers are packed in the HBox or VBox container in the order in which they appear in the structure. By combining HBox and VBox layouts for various containers, you can align the containers of your form in any way you choose.
See HBOX container and VBOX container in the Genero Business Development Language User Guide for more details.