// key = 1 to 12
static void registerCtrlFunctionKey(JFrame frame, int key, final Runnable r) {
  S name = "Ctrl+F" + key;
  Action action = abstractAction(name, r);
  JComponent pnl = frame.getRootPane();
  KeyStroke keyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_F1+key-1, InputEvent.CTRL_MASK);
  pnl.getActionMap().put(name, action);
  pnl.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(keyStroke, name);
}

Began life as a copy of #1003927