private void setupMenuBar() {
            saveAsItem = new JMenuItem("Save As...", 'A');
            saveAsItem.setAccelerator(KeyStroke.getKeyStroke("ctrl S"));
            setImage1Item = new JMenuItem("Set Image 1...", '1');
            setImage1Item.setAccelerator(KeyStroke.getKeyStroke("ctrl 1"));
            setImage2Item = new JMenuItem("Set Image 2...", '2');
            setImage2Item.setAccelerator(KeyStroke.getKeyStroke("ctrl 2"));
            
            JMenu file = new JMenu("File");
            file.setMnemonic('F');
            file.add(setImage1Item);
            file.add(setImage2Item);
            file.addSeparator();
            file.add(saveAsItem);
            
            JMenuBar bar = new JMenuBar();
            bar.add(file);
            
            // disabling menu bar to simplify code
            // frame.setJMenuBar(bar);
        }