Chosen library not working
I guess the Chosen library version 1.8.3 (released Jan on 22 2018) is a little bit too far ahead of the Chosen module version 7.x-2.1 (released on Mar 23 2017).

Replace the library by an older release (preferably version 1.1.0) and it should work.



From the Chosen module's README.txt:


-- INSTALLATION --

  1. Download the Chosen jQuery plugin
  (http://harvesthq.github.io/chosen/ version 1.1.0 is recommended)
  and extract the file under sites/all/libraries.
  2. ...