Dropdown menu not working after configuring my textarea with codemirror


I am working on a github project which is deployed here.

I configured codemirror in textarea to have syntax highlighting in my editor, and yes it looks cool now , but the problem is my language changer stopped working, have a look ,website with my pull request is deployed here.

Changes in my template here

Whole template is : https://gist.github.com/142ayushkumar/177db9e0649946a61785bcf72c60dd7a

Any help will be highly appreciated.