title: Ionic 2 keep sidemenu icon after navCtrl push
body: <p>When I navigate to a page using navCtrl.push, sidemenu icon (hamburger) is lost, and back icon is appearing instead of the sidemenu icon.</p>
  
  <p>What I want to do, is to keep the sidemenu icon (put it on the right side of the ion-navbar), and when pushing a page to navCtrl, have both back button and sidemenu icon.</p>
  
  <p>I use this piece of code in all pages:</p>
  
  <pre><code>&lt;ion-header&gt;
    &lt;ion-navbar&gt;
      &lt;button ion-button menuToggle right&gt;
        &lt;ion-icon name="menu"&gt;&lt;/ion-icon&gt;
      &lt;/button&gt;
      &lt;ion-title&gt;Post Offices&lt;/ion-title&gt;
    &lt;/ion-navbar&gt;
  &lt;/ion-header&gt;
  </code></pre>
  
  <p>And I use: </p>
  
  <pre><code>this.navCtrl.push(Page)
  </code></pre>
  
  <p>And it works fine (I lose the menu icon though, but there is no other problem).</p>