New Twiddle

components.click-away.js

import Ember from 'ember';

export default Ember.Component.extend({
  classNames: ['click-away'],
  attributeBindings: ['tabindex'],
  tabindex: -1,
  didInsertElement() {
    this._super(...arguments);
    this.element.focus()
  },
  focusOut() {
    if (typeof this.clickedAway === 'function') {
      this.clickedAway.call();
    }
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  isOpened: false,
  
  open() {
    this.set('isOpened', true);
  },
  
  close() {
    this.set('isOpened', false);
  }
});

styles.app.css

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

.click-away:focus {
  outline: 1px solid black;
}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<button tabIndex="0" {{action this.open}}>Open</button>
<br>
<br>
<input tabindex="1" value="before" />

{{#if this.isOpened}}
  <ClickAway @clickedAway={{action this.close}}>
    <p>WOWWWWWWWW</p>
    <p>Click somewhere else or press tab!</p>
  </ClickAway>
{{/if}}

<input tabindex="2" value="after" />
<br>
<br>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}