tabbable menu

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

.container {
  background: rgba(0, 0, 0, .6);
  color: #fff;
}

.menu {
  max-height: 0;
  overflow: hidden;
}

.container:hover > .menu,
.container:focus > .menu {
  max-height: 150px;
}

.item:hover,
.item:focus {
  background: rgba(0, 0, 0, .2);
}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<div class="container" tabindex="-1">
  <p>Items</p>
  <div class="menu">
    <div class="item" tabindex="0">
      Item 1
    </div>
    <div class="item" tabindex="0">
      Item 2
    </div>
    <div class="item" tabindex="0">
      Item 3
    </div>
    <div class="item" tabindex="0">
      Item 4
    </div>
  </div>
</div>

twiddle.json

{
  "version": "0.10.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.1",
    "ember-template-compiler": "2.6.0"
  },
  "addons": {}
}