Non-transpiled JavaScript causing issues while using NGG block in editor.

We try to support the last version of Internet Explorer which appears to be the last holdout of browsers not supporting this feature; in this case we recently upgraded a third party library (select2) and probably aren’t going to invest the time into forking select2. I do however intend soon to make it optional to disable select2 so that users can use a plain HTML <select> if they prefer — that would indirectly solve your issue. Sorry!