This class should be treated as a "protected" inner class. Instantiate it only within subclasses of MetalComboBoxUI. This class is now obsolete and doesn't do anything and is only included for backwards API compatibility. Do not call or override.
This is a utility method that helps event handlers figure out where to send the focus when the popup is brought up. The standard implementation delegates the focus to the editor (if the combo box is editable) or to the JComboBox if it is not editable.