title: ngb-modal not opening correctly
body: <p>Copying the demo code from the modal-basic example, I'm having this problem. The modal window is displayed within the root HTML, not in a new window with a black backdrop as it should be. Any ideas? I'm using angular CLI and installed popper.js, jquery, ngb and bootstrap. </p>
  
  <p>The code is absolutely the same as the first example from this URL:
  <a href="https://ng-bootstrap.github.io/#/components/modal/examples" rel="nofollow noreferrer">https://ng-bootstrap.github.io/#/components/modal/examples</a></p>
  
  <p>only difference is there's a (click) on a <li> that opens the modal but it uses the same function as the example</p>
  
  <p>Here's a GIF with the problem
  <a href="https://i.stack.imgur.com/LEKXm.gif" rel="nofollow noreferrer">The Problem Itself</a></p>