docs: protected final JButton getButtonOK() {
          if (buttonOK == null) {
              buttonOK = new JButton();
              buttonOK.setText("OK");
              buttonOK.setPreferredSize(new Dimension(80, 26));
              buttonOK.addActionListener(new ActionListener() {
                  public void actionPerformed(final ActionEvent e) {
                      if (destDirSelector != null) {
                          destDirSelector.ok();
                      }
                  }
              });
          }
          return buttonOK;
      }