Select2 tabindex issue

i am using select2 v4.0.3 in my project. there is a page in which i have given tab index to all elements. (input, select2, textarea etc). and there is a functionality that i can add or remove any elements of any type. now i have wrote a script that perform described below.

on add any element a foreach loop find all element which has tabindex and reindex of every element’s tab index from 1. but when there is select2 arrives there are multiple span has tabindex value and i can not alter the element or it’s value of span.select2-selection select2-selection–single

inshort tab index is not proper working because select2’s spanselect2-selection select2-selection–single remaining to -1 alway and can not changable.