title: ng-select CSS issues, bootstrap input-sm
body: <p>So while using ng-select on a reactive form, I'm trying to style the field on error (invalid) like this.</p>
  
  <p>the field:</p>
  
  <pre><code>&lt;ng-select class="form-control input-sm" [class.store-error]="showError('store')"...
  </code></pre>
  
  <p>The show error method looks like this - and works for ALL OTHER FORM FIELDS </p>
  
  <pre><code>showError (fieldName: string) {
      const field = this.form.get(fieldName);
      return field.invalid &amp;&amp; (field.touched || this.submitAttempted);
  }
  </code></pre>
  
  <p>ng select does not change classes. </p>
  
  <p>It appears as though ng-select constructs a div on top of a form field element, and changing the bootstrap class to input-sm exposes this (so a secondary question is how to get the input-sm applied to ng-select)</p>
  
  <p><a href="https://i.stack.imgur.com/A0XsS.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/A0XsS.jpg" alt="enter image description here"></a></p>
  
  <p>this CSS isse is secondary to the field NOT showing invalid using css-binding.
  Has anyone solved this?</p>
  
  <p><a href="https://i.stack.imgur.com/gkrDE.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gkrDE.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/gkrDE.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gkrDE.jpg" alt="You can see here that the containing div is taking the css, but ng-selects generated div is not...so the annomoly of applying the input-sm style, revealed a bug - as the ng-select doesn&#39;t inherit the style"></a></p>