@Override
  public void refresh() {
    if (fCurrentInput == null) {
      clearFields();
    } else {
      setValue(IEnvironment.P_OS);
      setValue(IEnvironment.P_WS);
      setValue(IEnvironment.P_ARCH);
      setValue(IEnvironment.P_NL);
    }

    fOsText.setEditable(fCurrentInput != null && isEditable());
    fWsText.setEditable(fCurrentInput != null && isEditable());
    fNlText.setEditable(fCurrentInput != null && isEditable());
    fArchText.setEditable(fCurrentInput != null && isEditable());

    super.refresh();
  }