public void checkCalculationEnabled() {
        if (lstDays.getSelectionModel().getSelectedIndex() == -1) {
            btnCalculate.setDisable(true);
        }else if (!optToday.isSelected() && !optTomorrow.isSelected()) {
            btnCalculate.setDisable(true);
        }else{
            btnCalculate.setDisable(false);
        }
        special();
    }