title: Bootbox showing white box behind dialog
body: <p>I am using bootbox plugin v4.3.0 with metronic and laravel and having this strange issue;</p>
  
  <p><img src="https://i.stack.imgur.com/AOa9x.png" alt="enter image description here"></p>
  
  <h2>JS</h2>
  
  <pre><code>$('#signup').click(function()
  {
      bootbox.alert('some message');
  }
  </code></pre>
  
  <h2>Rendered HTML</h2>
  
  <pre><code>&lt;div style="z-index: 10051;" class="modal-scrollable"&gt;
    &lt;div aria-hidden="false" style="display: block; margin-top: -88px;" class="bootbox modal fade bootbox-alert in" tabindex="-1" role="dialog"&gt;
      &lt;div class="modal-dialog modal-lg"&gt;
        &lt;div class="modal-content"&gt;
          &lt;div class="modal-body"&gt;
            &lt;button style="margin-top: -10px;" type="button" class="bootbox-close-button close" data-dismiss="modal" aria-hidden="true"&gt;×&lt;/button&gt;
            &lt;div class="bootbox-body"&gt;ll&lt;/div&gt;
          &lt;/div&gt;
          &lt;div class="modal-footer"&gt;
            &lt;button data-bb-handler="ok" type="button" class="btn btn-primary"&gt;OK&lt;/button&gt;
          &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>