private void initComponents() {
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        selectFileLbl = new JLabel();
        backBtn = new JButton();
        statusLbl = new JLabel();
        sectionScrollPane = new JScrollPane();
        sectionListTable = new JTable();
        addFileBtn = new JButton();

        //======== this ========
        setTitle("Learning words - Import words");
        setResizable(false);
        Container contentPane = getContentPane();
        contentPane.setLayout(null);

        //---- selectFileLbl ----
        selectFileLbl.setText("Select file:");
        selectFileLbl.setFont(new Font("Segoe UI", Font.BOLD, 14));
        contentPane.add(selectFileLbl);
        selectFileLbl.setBounds(new Rectangle(new Point(15, 15), selectFileLbl.getPreferredSize()));

        //---- backBtn ----
        backBtn.setText("Back");
        contentPane.add(backBtn);
        backBtn.setBounds(95, 45, 75, 30);
        backBtn.addActionListener(new BackButtonListener(this, user));

        //---- statusLbl ----
        statusLbl.setText("Select section and choose excel file to import words. Duplicate words won't be imported!");
        statusLbl.setFont(new Font("Segoe UI", Font.BOLD, 12));
        contentPane.add(statusLbl);
        statusLbl.setBounds(new Rectangle(new Point(15, 295), statusLbl.getPreferredSize()));

        //======== sectionScrollPane ========
        {
            sectionScrollPane.setViewportView(sectionListTable);
        }
        contentPane.add(sectionScrollPane);
        final SelectSectionTableModel model = new SelectSectionTableModel();
        sectionListTable.setModel(model);
        sectionListTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        sectionListTable.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                try {
                    int row = sectionListTable.getSelectedRow();
                    selectedSection = (model.getValueAt(row, 0)).toString();
                    selectedSectionId = (Integer)(model.getId(selectedSection));
                    System.out.println(selectedSectionId);
                    if (!addFileBtn.isEnabled()) {
                        addFileBtn.setEnabled(true);
                    }
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        });
        sectionScrollPane.setBounds(15, 85, 595, 185);

        //---- addFileBtn ----
        addFileBtn.setText("Add file");
        contentPane.add(addFileBtn);
        addFileBtn.setBounds(15, 45, 75, 30);
        addFileBtn.setEnabled(false);
        addFileBtn.addActionListener(new AddFileButtonListener(statusLbl));

        contentPane.setPreferredSize(new Dimension(640, 360));
        pack();
        setLocationRelativeTo(getOwner());
    }