FIX: disabled combo-box attribute had no effect

app/assets/javascripts/discourse/components/combo-box.js.es6

@@ -2,7 +2,7 @@ import { on, observes } from 'ember-addons/ember-computed-decorators';
 
 export default Ember.Component.extend({
   tagName: 'select',
-  attributeBindings: ['tabindex'],
+  attributeBindings: ['tabindex', 'disabled'],
   classNames: ['combobox'],
   valueAttribute: 'id',
   nameProperty: 'name',

app/assets/stylesheets/common/base/combobox.scss

@@ -39,6 +39,9 @@
   &.select2-container-active {
     border-color: $tertiary;
   }
+  &.select2-container-disabled .select2-chosen {
+    color: blend-primary-secondary(50%);
+  }
 }
 
 .select2-container-multi .select2-choices {