You could override the selection code in your JComboBox
model, with code such as the following SSCCE:
public class JComboExample {
private static JFrame frame = new JFrame();
private static final String NOT_SELECTABLE_OPTION = " - Select an Option - ";
private static final String NORMAL_OPTION = "Normal Option";
public static void main(String[] args) throws Exception {
JComboBox<String> comboBox = new JComboBox<String>();
comboBox.setModel(new DefaultComboBoxModel<String>() {
private static final long serialVersionUID = 1L;
boolean selectionAllowed = true;
@Override
public void setSelectedItem(Object anObject) {
if (!NOT_SELECTABLE_OPTION.equals(anObject)) {
super.setSelectedItem(anObject);
} else if (selectionAllowed) {
// Allow this just once
selectionAllowed = false;
super.setSelectedItem(anObject);
}
}
});
comboBox.addItem(NOT_SELECTABLE_OPTION);
comboBox.addItem(NORMAL_OPTION);
frame.add(comboBox);
frame.pack();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
frame.setVisible(true);
}
});
}
}
This will display a combo box with the intial selection of "- Select an Option -
". As soon as the user selects another option, it will not be possible to select the original option again.