Needs tests

User pain Issue Created
54% details#1988968: Drupal.ajax does not guarantee that "add new JS file to page" commands have finished before calling said JS 2013-05-08
50% details#2508796: Query string is appended multiple time after each AJAX request 2015-06-20
45% details#2493945: Views filters dragging in the grouping view is broken 2015-05-23
43% details#2498915: Javascript DrupalBehavior error when JQuery UI Dialog not defined in Behavior settings 2015-06-02
43% details#2903614: [PP-1] Race condition results in same CSS+JS being loaded twice: race between BigPipe's server-side dynamic asset loading and Quick… 2017-08-21
34% details#2863444: Discourage/make impossible to select a "to" date that is before the "from" date 2017-03-23
29% details#1149078: States API doesn't work with multiple select fields 2011-05-13
29% details#2627788: Focus state bug on text field AJAX calls 2015-12-03
29% details#2648460: AJAX view with exposed filters & default values does not respect user's empty choice 2016-01-11
29% details#2661880: Quick Edit doesn't work for Custom Blocks referenced by other Custom Blocks 2016-02-03
29% details#2692453: When entire form is replaced by an Ajax response, Drupal.attachBehaviors() is called on an orphaned DOM node 2016-03-22
29% details#2784495: Normalize block place and outside-in experiences 2016-08-15
29% details#2834346: Contextual links double trigger 2016-12-09
29% details#2845161: States API doesn't work with default null value on select type and #multiple or #size option 2017-01-20
29% details#2855521: Drupalimage calling drupallink functions without checking if the plugin is loaded 2017-05-16
29% details#2880338: Empty state (filled) doesn't work for date field with datepicker plugin 2017-05-22
29% details#2895477: Native browser form validation does not fire when submit buttons use #ajax 2017-07-17
26% details#2367655: Control the list of behaviors run by Drupal.attachBehaviors 2014-11-02
26% details#2560457: Support drag-and-drop image uploads in CKEditor 2015-08-31
23% details#1838234: Add jQuery Timepicker for the Time element of the datetime field 2012-11-12
23% details#1864944: Tests for ajaxPageState does not contain JS files that are in scopes other than 'header' 2012-12-12
23% details#2359711: Improve Error Message of "Authored By" 2015-02-19
23% details#2755223: Consider letting EditorImageDialog return canonical public:// file URLs and let the drupalimage CKEditor plugin transform those to the… 2016-06-24
21% details#1920876: Add a tiny bit of state magic in the image.module and hide the Title and Alt groups when the related form items are disabled 2013-02-19
21% details#2805499: Provide screen reader feedback when Views List is filtered by name or description 2016-09-23
21% details#2807241: Funky code in Views UI to make Add display list doesn't work in non-English languages 2016-09-27
17% details#2731991: Setting required on radios marks all options required 2016-05-24
17% details#2752511: Update location.hash when clicking a vertical tab 2016-06-21
17% details#2793343: Dialog drupalAutoButtons option should be respected on initial load 2016-09-01
17% details#2853039: Currently appears to be no way to activate Tours for users in the front end 2017-02-16
14% details#1587536: JS aggregation should account for "defer" and "async" attributes 2012-05-29
14% details#2620748: Recoverable fatal error: Argument 1 passed to Drupal\comment\CommentManager::getCountNewComments() 2015-11-22
14% details#2796885: field_ui.js hard-codes region names which are alterable 2016-09-08
9% details#2254935: Use a modal for content entity form delete link 2014-04-30

Sorting of the JavaScript issue queues based on user pain rating.

User pain = Type * Priority * Public / Max score

Highlighted rows are killer issues , issues that take a significant effort to fix due to their complexity.