Get category dropdown / multiple scheduler in same WP site

Searching for a solution to have three different schedulers, I found in a post that I can achieve that creating categories, and then using the following code:

$scheduler .= " scheduler._filter_by = ''; scheduler.filter_day = scheduler.filter_week = scheduler.filter_month = function(id){ if (!scheduler._filter_by) return true; if (scheduler.getEvent(id).category == scheduler._filter_by) return true; return false; }; </script> <select onchange='scheduler._filter_by = this.value;scheduler.setCurrentView(scheduler._date);'> <option value=''>Toutes</option> <option value='category_0'>Group A</option> <option value='category_1'>Group B</option> <option value='category_2'>Group C</option> </select>";[code]


where the above code will replace $scheduler .= "</script>";

I tried that, but I don’t see any dropdown there in the page. Am I doing anything wrong, or probably there’s another way to have multiple schedular on the same site ?

Here is a screen shot of my categories:

For information, I’m using WP 5.3.1 and I believe the scheduler is version 3.0 since I am seeing

in the readme file.