The sample output at the bottom demonstrates the receipt of an "off" event immediately prior to the arrival of the corresponding "on" event.
Also included in the example is a preview of the new Box container. Box is a panel that comes with a BoxLayout as its default layout manager. BoxLayout is useful if you want to lay out a single row or a single column of components within a container. [Topley, p151]
BoxLayout will be discussed in detail later.
[Reference: Topley, pp583-590]