+ KeyStroke octave2Key = KeyStroke.getKeyStroke(KeyEvent.VK_F9, 0);
+ KeyStroke octave4Key = KeyStroke.getKeyStroke(KeyEvent.VK_F10, 0);
+ KeyStroke octave6Key = KeyStroke.getKeyStroke(KeyEvent.VK_F11, 0);
+ KeyStroke octave8Key = KeyStroke.getKeyStroke(KeyEvent.VK_F12, 0);