title: Angular 2: Form submission canceled because the form is not connected
body: <p>I have a modal that contains a form, when the modal is destroyed I get the following error in the console:</p>
  
  <blockquote>
    <p>Form submission canceled because the form is not connected</p>
  </blockquote>
  
  <p>The modal is added to a <code>&lt;modal-placeholder&gt;</code> element which is a direct child to <code>&lt;app-root&gt;</code>, my top level element. </p>
  
  <p>What's the correct way to removing a form from the DOM and getting rid of this error in Angular 2? I currently use <code>componentRef.destroy();</code> </p>