unclickable components in JTable (TableCellRenderer)

Question

I used a custom cell render for JTable that contains a JTextfield and JCombobox but the problem that I can't click on them like the are disabled!
this is my code:

public class OvertimeAndProjectRender extends JPanel implements TableCellRenderer{

    /**
     * 
     */
    private static final long serialVersionUID = 2079139315339181747L;
    Project p = new Project();
    private List<Project> listProject;
    JComboBox<ComboItem> projectComboBox = new JComboBox<ComboItem>();
    public  OvertimeAndProjectRender(int idChef) {
        listProject = p.getListProjectsForSelectedChef(idChef);
        fillCombobox();
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value,boolean isSelected, boolean hasFocus, int row, int column) {
        this.setLayout(new BorderLayout(0, 0));
        JTextField t = new JTextField();
        this.add(t, BorderLayout.NORTH);
        this.add(projectComboBox, BorderLayout.SOUTH);
        return this;
    }

    private void fillCombobox() {
        int nbIde = listProject.size();
        for(int i=0; i<nbIde; i++){     
            String key = Integer.toString(listProject.get(i).getId());
            String value = listProject.get(i).getDesignation();
            projectComboBox.addItem(new ComboItem(key, value));
        }
    }


}

And this how I called the custom cellRender:

tablePointage.getColumnModel().getColumn(2).setCellRenderer(new OvertimeAndProjectRender(idChef));

And this is the picture of JTable:

_{(source: hostingpics.net)}