private void initInterface()
        {
            this.setLayout(new GridLayout(4, 5, 5, 5));
            
            for (String path : CommonData.getExpressionPathVector())
            {
                JLabel label = new JLabel(new ImageIcon(path));
                label.addMouseListener(this);
                label.setBorder(new TitledBorder(""));
                this.add(label);
            }
            
            this.setBorder(new TitledBorder("Expression"));
            this.setBackground(Color.white);
        }