Modifying the All-in-One Event Calendar plugin : how to hang up an event?

Hello! There is a wonderful plug-in All-in-One Event Calendar. So, we decided to make the output of events in the calendar of colored circles instead of text.

Initial situation:
I had written a function that changes all event titles to a circle symbol:
...innerHTML = '●'
It works, when the page loads, all the event titles are changing on rounds (see screenshot: https://pixs.ru/showimage/kalendarpn_7045746_29118809.png)
But when you go to the next month/year, these event-titles are displayed again:
https://pixs.ru/showimage/kalendar1p_6985379_29118825.png

What I tried to do with:
When you click on the next month, the query is executed by the link
https://next-space.com.ua/calendar/action~month/exact_date~1522530000/request_format~json/?callback=jQuery200100655182355666537_1516820488824&request_type=jsonp&ai1ec_doing_ajax=true&_=1516820488827
I tried to use

jQuery( document ).ajaxStart(function() {
  ...
});

But, apparently, this ajax-query is not global, so nothing worked.

Expected result:
When the query is sending and new month is loaded, my function is executed, which turns the text into a round symbol