Fixed weird gl dropdown error... 🙈

app/assets/javascripts/boards/components/milestone_select.js

+/* global BoardService */
 /* global Vue */
 module.exports = Vue.extend({
   props: {

app/assets/javascripts/gl_dropdown.js

@@ -534,9 +534,13 @@
     GitLabDropdown.prototype.renderItem = function(data, group, index) {
       var field, fieldName, html, selected, text, url, value, rowHidden;
 
-      value = this.options.id ? this.options.id(data) : data.id;
+      if (!this.options.renderRow) {
+        value = this.options.id ? this.options.id(data) : data.id;
 
-      if (value) { value = value.toString().replace(/'/g, '\\\''); }
+        if (value) {
+          value = value.toString().replace(/'/g, '\\\'');
+        }
+      }
 
       // Hide element
       if (this.options.hideRow && this.options.hideRow(value)) {

spec/javascripts/boards/milestone_select_spec.js

 /* global Vue */
 /* global boardsMockInterceptor */
+/* global boardObj */
 /* global BoardService */
 const MilestoneComp = require('~/boards/components/milestone_select');
 require('~/boards/services/board_service');
@@ -59,7 +60,7 @@ describe('Milestone select component', () => {
         expect(vm.$el.querySelector('.fa-spinner')).toBeNull();
         expect(vm.$el.querySelectorAll('.board-milestone-list li').length).toBe(3);
         expect(
-          vm.$el.querySelectorAll('.board-milestone-list li')[2].textContent
+          vm.$el.querySelectorAll('.board-milestone-list li')[2].textContent,
         ).toContain('test');
       });