I am trying to locate checkboxes in JFreeChart and also I want to manage them in a combo box. How can I locate them and then how can I make them in combo box?

My checkboxes look like this:

As I said before I want to show them in a combo box at the upper left of the chart. My code looks like this:

for(int i = 0 ; i< dataIndex; i++)
{
    JCheckBox checkBox = new JCheckBox( new VisibleAction(name,renderer,i));
    checkBox.setSelected(true);
    renderer.setSeriesVisible(i,true);
    controlPanel.add(checkBox);
    checkBox.setFont(controlPanelFont);
}