public void actionPerformed(ActionEvent e) {
        if (e.getSource() == showPitch) changeDataType(PITCH);
        if (e.getSource() == showRhythm) changeDataType(RHYTHM);
        if (e.getSource() == showDynamic) changeDataType(DYNAMIC);
        if (e.getSource() == showPan) changeDataType(PAN);
        if (e.getSource() == open) openMIDIFile();
        if (e.getSource() == openXml) openXMLFile();
        if (e.getSource() == saveAs) histo.saveData();
        if (e.getSource() == quit) System.exit(0);

    }