slider.addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent event) {
                JSlider source = (JSlider)event.getSource();
                if (!source.getValueIsAdjusting()) {
                    int value = (int)source.getValue();
                    int size = freeChartPanel.getDots().size();
                    size = size*value/100;
                    freeChartPanel.drawCurrentSize(size);
                }

            }
        });