title: ionic Popover content position issue
body: <p>I've implemented a popover with number keys on it using this library <a href="https://github.com/alvarowolfx/ng-keypad" rel="nofollow noreferrer">https://github.com/alvarowolfx/ng-keypad</a>.
  When I click on an input field, the popover appears. But, sometimes the position of content of popover is not correct.
  Can you please help me.</p>
  
  <p>Here is my html:</p>
  
  <pre><code>&lt;script id="keypad-popover.html" type="text/ng-template"&gt;
    &lt;ion-popover-view class="aiv-keypad"&gt;
      &lt;ion-content overflow-scroll=false&gt;
          &lt;div class="ios"&gt;
              &lt;ng-keypad on-key-pressed='onKeyPressed'&gt;
                  &lt;ng-key ng-repeat='key in aivkeys' ng-key-data='key' ng-key-type='keypad.type'&gt;{{key}}&lt;/ng-key&gt;
                  &lt;!--&lt;ng-key ng-key-type='keypad.type' ng-key-data="keypad.data"&gt;{{keypad.data}}&lt;/ng-key&gt;--&gt;
              &lt;/ng-keypad&gt;
          &lt;/div&gt;
      &lt;/ion-content&gt;
    &lt;/ion-popover-view&gt;
  &lt;/script&gt;
  </code></pre>
  
  <p>In controller,</p>
  
  <pre><code>$ionicPopover.fromTemplateUrl('keypad-popover.html', {
      scope: $scope,
      backdropClickToClose:false
  }).then(function(popover) {
      $scope.keypad_popover = popover;
  });
  </code></pre>
  
  <p>Expected,</p>
  
  <p><a href="https://i.stack.imgur.com/bGxqy.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bGxqy.jpg" alt="enter image description here"></a></p>
  
  <p>Sometimes, this problem occurs,</p>
  
  <p><a href="https://i.stack.imgur.com/23Gon.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/23Gon.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/SX2om.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SX2om.jpg" alt="enter image description here"></a></p>