Breaks toolbar due to z-index getting unset

Problem/Motivation

Z-index is getting a value of unset which breaks integration with toolbar.

    Drupal.behaviors.ief_popup = {
        attach: function (context, settings) {

            /* make sure the Drupal toolbar is placed behind the IEF Complex Widget Dialog */
            if ($(".ief-popup-wrapper", context).length > 0) {
                $(".toolbar").css("position", "relative");
                $(".toolbar").css("z-index",  1);
            }
            else {
                $(".toolbar").css("z-index",  "unset");
            }
          $(".toolbar").css("z-index",  "unset");
.
.
.

Steps to reproduce

* Install the module
* Confirm toolbar haz z-index issues, specially on gin with the shortcuts menu.

Proposed resolution

Fix JS