title: IONIC2 Background image is resized when keyboard is open
body: <p>Using ionic-2 when a background image is set and it's size (background-size) is set to 'cover' or '100% 100%' such as:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>background: url("../../img/bg.jpeg");
  background-repeat: no-repeat;
  background-size: cover;</code></pre>
  </div>
  </div>
  </p>
  
  <p>When the keyboard is opened the background image is resized, how can this be avoided? (So that the background image size remains the same even though the keyboard has shrunk the content)</p>