testLayoutFctButtons = (keyboard, callback) => {
    let fctBtnCount = 0;
    let fctBtnHasOnclickCount = 0;

    keyboard.recurseButtons((button) => {
      const label = button.getAttribute("data-skbtn");

      if(!label.includes("{") && !label.includes("}"))
        return false;

      fctBtnCount++;

      if(button.onclick){
        button.onclick();
        fctBtnHasOnclickCount++;
      }

      callback(fctBtnCount, fctBtnHasOnclickCount);
    });
  }
Test if function buttons are interactive (have an onclick)