The Event Library is used by the GUI Library (i.e., by the Tweek Java GUI) to inform Panel Beans about GUI events. This includes events such as GUI iconification, GUI closing, and the gaining and losing of focus by the GUI. The Event Library is found in $TWEEK_BASE_DIR/share/tweek/java/TweekEvents.jar.

An interesting part of the Event Library is the Event Listener Registry. Historically, the Tweek Java GUI has performed automatic, run-time registration of Beans as event listeners based on the interface(s) that the Beans implement. That is not always convenient, however. For example, a Panel Bean author may want to use utility classes as event listeners rather than the Panel Bean itself. In this case, the utility classes can be registered manually with the Tweek Java GUI using the Event Listener Registry.