jQuery UI selectmenu: Why is "select" event not triggered?

Question

I am having the issue in a project so I tried this on a fiddle. I am trying to trigger the select of a selectmenu dynamically. Why is the select event that I defined within the initialization of the selectmenu only firing after I did a manual selection?

I know this is possible by running $("#myselect").on("selectmenuselect") but why does it not work as suggested by the API?

$(function () {
   $("#myselect").selectmenu({
       select: function () {
           alert("ok");
       }
   });
   setTimeout(function () {
       $("#myselect").val("option4");
       $("#myselect").selectmenu("refresh");
       $("#myselect").trigger("selectmenuselect");
    }, 1000);
})

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/themes/smoothness/jquery-ui.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script>

<select id="myselect">
  <option value="option1" selected>option 1</option>
  <option value="option2">option 2</option>
  <option value="option3">option 3</option>
  <option value="option4">option 4</option>
</select>

Answer 1

Something like this should do the trick:

$(function () {      
  
    $("#myselect").selectmenu().on("selectmenuselect", function (event, ui) {
         console.log(ui);
    });
  
   setTimeout(function () {
       $("#myselect").val("option4");
       $("#myselect").selectmenu("refresh");
       $("#myselect").trigger("selectmenuselect",$("#myselect"));
    }, 1000);
})

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/themes/smoothness/jquery-ui.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script>

<select id="myselect">
  <option value="option1" selected>option 1</option>
  <option value="option2">option 2</option>
  <option value="option3">option 3</option>
  <option value="option4">option 4</option>
</select>