The current version of GUI Builder doesn't have any categorization of event handlers. All event handlers are just sorted alphabetically and presented to the user. This works somehow only because the most important event handler (actionPerformed) is the first in the alphabet. But there are components whose the most important handler is buried deep in the list, for example stateChanged handler of JSlider.

It would be nice to categorize the event handlers in a similar way as properties are categorized. Also it would be helpful to modify Events menu to have the most important event handlers at the top.

There are several methods that claim to provide the required info:

BeanInfo.getDefaultEventIndex()
EventSetDescriptor.isInDefaultEventSet()
EventSetDescriptor.isExpert()
EventSetDescriptor.isPrefered()

Unfortunately, these methods don't seem to return any useful information when called on default BeanInfo(s)/EventSetDescriptor(s).