Hi tullio0106,
Thank you for creating a code example of this issue with which I was able to duplicate it.
I have two option for which eliminate this issue.
The first one is replace the code in your script tag with this code snippet:

    <script type="text/javascript">
        window.onload = () => {
             let combobox = document.querySelectorAll('smart-combo-box');
             for (let i = 0; i < combobox.length; i++) {
                combobox[i].onchange = function (event) {
        function eseguiRefresh() {
            alert("test "+event.currentTarget.id);
         function mostraAlertMsgOption(elem) {

With the code above you don’t need to bind to ‘this’ like in the rest of your code in your example to get the combobox id and you can remove the eseguiRefresh() function from the smart-combo-boxx itself.
Also the shouldn’t be a problem to use our components with other libraries like with the ones you mentioned.
One other thing to mention is that I tested your code with my previous solution and it worked.
In the smart-combo-box I used selected-indexes instead of selected-values like you do in your code example and with selected-indexes the issue was not present at all.
However if the problem still persists I will be glad to be able to help you again!
Please, do not hesitate to contact us if you have any additional questions.
Best regards,
Yavor Dashev
Smart UI Team