title: in Ionic v3 suddenly I am getting this error cannot read _getPortal from undefined
body: <p>I am getting this error in ionic v3 whenever I call a ModalController or an AlertController. It seems _appRoot is not defined. Any ideas how to fix this?</p>
  
  <pre><code>core.js:1449 ERROR Error: Uncaught (in promise): TypeError: Cannot read property '_getPortal' of undefined
  TypeError: Cannot read property '_getPortal' of undefined
      at App.present (app.js:241)
      at Alert.present (alert.js:101)
      at TaskDetailPage.&lt;anonymous&gt; (task-detail.ts:112)
  </code></pre>