initialType != null ? absMagEqns.get(initialType) : "",
true, false, Kind.LINE);
final SelectableTextField typesField = new SelectableTextField(
"Variable Type", types, initialType);
typesField.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// Update the abs mag equation when the variable type
// selection changes.
absMagEqns.get(typesField.getValue());