private void updateMnemonic(int lastMnemonic, int mnemonic) {
    if (mnemonic == lastMnemonic) {
      return;
    }
    InputMap windowInputMap = SwingUtilities.getUIInputMap(
      this, JComponent.WHEN_IN_FOCUSED_WINDOW);

    int mask = SystemInfo.isMac ? InputEvent.ALT_MASK | InputEvent.CTRL_MASK : InputEvent.ALT_MASK;
    if (lastMnemonic != 0 && windowInputMap != null) {
      windowInputMap.remove(KeyStroke.getKeyStroke(lastMnemonic, mask, false));
    }
    if (mnemonic != 0) {
      if (windowInputMap == null) {
        windowInputMap = new ComponentInputMapUIResource(this);
        SwingUtilities.replaceUIInputMap(this, JComponent.
          WHEN_IN_FOCUSED_WINDOW, windowInputMap);
      }
      windowInputMap.put(KeyStroke.getKeyStroke(mnemonic, mask, false), "doClick");
    }
  }
private void updateMnemonic(int lastMnemonic, int mnemonic)