JComboBox pure craziness

Someone asked me why his ItemListener, attached to a JComboBox, was getting two events when he selected something on it. Weird.

I looked up JComboBox' javadocs, just to be sured, and....this is what I found:

Adds an ItemListener.

aListener will receive one or two ItemEvents when the selected item changes.

I understand Swing is a huge framework and it has its rough edges...but this? It certainly looks like someone couldn't fix this strange behavior, and desided to make it a documented feature instead. Way to go!