Impressed by a cool feature I didn't know about. If you have some JavaBean, like my Event class below, you can right-click it and choose "BeanInfo Editor":

Now, as you can see above, I don't have a BeanInfo class. So I am now asked whether the IDE should create one for me. So I say OK and then I have a new BeanInfo class, generated from my Event class, as well as a multiview editor for visually editing the BeanInfo class:

Thanks Eric and Nicklas from Artificial Solutions in Stockholm for pointing this out to me today. It comes in very handy in NetBeans Platform applications when you're working with a BeanNode and want to customize the display of your properties.