The JComboBox in SwingSet that is in the lower left hand corner of the combobox panel is not responding properly to mouse events. It only happens the first time you try to interact with it. Once you get it to pop down a menu, it works from then on. To reproduce:

1. Launch SwingSet
2. Go to ComboBox panel
3. Click once on the lower left combobox
4. Click a second time on the lower left combobox
5. Click a third time on the lower left combobox

After that, the combobox brings down the menu.