Select2 with Ajax is not sending request

Finally resolved the issue.

<input> is not supported in select2 v4

.You have to use <select> element instead

In my case, it was a general select2-call of .select2-Elements in the footer of all my templates:

$('.select2').select2();

Event though my select for the Ajax-Request didn't have that class at all (I called it via an id), I had to change the above to

$('select.select2').select2({theme: 'classic'});

I guess select2() creates several elements with the class .select2, so that might interfere