title: Add a custom CSS class to all angular-formio/formio elements
body: <p>I'm attempting to embed <a href="https://github.com/formio/angular-formio" rel="nofollow noreferrer">angular-formio</a> in an Iconic 4 PWA application. As far as I can tell, formio does not include a template for Ionic. So I have reverted to using <a href="https://github.com/toert/Isolated-Bootstrap" rel="nofollow noreferrer">Isolated-Bootstrap</a> as a workaround. This lets me do the following:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;div class="ion-padding"&gt;
    &lt;div class="bootstrap"&gt;
      &lt;form-builder [form]="{
        components: []
      }"&gt;&lt;/form-builder&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>where I'm wrapping the angular-formio <code>&lt;form-builder&gt;</code> element in a div with the <code>bootstrap</code> CSS class. This works well and seems to let the Ionic and Bootstrap styles coexist. I will need to apply a few CSS tweaks to get it <em>just right</em> but its workable for now.</p>
  
  <p>The issue I have is that formio pops it's own dialogs for editing form elements. These dialogs are inserted into the DOM outside of this element and therefore do not have the required <code>bootstrap</code> CSS class.</p>
  
  <p>Is there any way I can tell angular-formio, or the underlying formio.js to add a CSS class to all of its elements and dialogs so that Isolated-Bootstrap will be applied to those elements?</p>