title: ckeditor how to allow for .insertHtml("<customTag myAttr='value'"></customTag>")
body: <pre><code>var currentDialog = CKEDITOR.dialog.getCurrent();
  currentDialog._.editor.insertHtml("&lt;customTag myAttr='var'&gt;&lt;/customTag&gt;");
  </code></pre>
  
  <p>Throws an error, <code>TypeError: Cannot read property 'isBlock' of undefined</code></p>
  
  <p>If I try <code>.insertHtml("&lt;span&gt;hello&lt;/span&gt;")</code> it works just fine.</p>
  
  <p>How can I change ckeditor to allow me to specify my own custom html tags via <code>.insertHtml()</code>? I'd love to just change it to be something like <code>&lt;span class='custom'...</code> or something like that, but I'm having to deal with legacy CMS articles. Using latest ckeditor. Thanks.</p>