private void multiplyTempo() {
        String txt = tempoField.getText();
        if (txt != null) {
            int num = 1;
            try {
                num = Integer.parseInt(txt);
            } catch (NumberFormatException e) {
                return;
            }
            if (num <= 1)
                return;
            ArrayList<StaffNoteLine> s = theStaff.getSequence().getTheLines();
            ArrayList<StaffNoteLine> n = new ArrayList<StaffNoteLine>();
            for (int i = 0; i < s.size(); i++) {
                n.add(s.get(i));
                for (int j = 0; j < num - 1; j++)
                    n.add(new StaffNoteLine());
            }
            s.clear();
            s.addAll(n);
            StateMachine.setTempo(theStaff.getSequence().getTempo() * num);
            theStaff.updateCurrTempo();
            theStaff.getControlPanel().getScrollbar()
                    .setMax(s.size() - Values.NOTELINES_IN_THE_WINDOW);
        }
    }