title: TinyMCE -> Cannot read property 'setAttribute' of null
body: <p>so I'm making an MVC site that needs a HTML input box.
  I have a text area that loads from an ajax dialog window. I understand that TinyMCE needs me to remove the control when i hide the dialog, that is fine.</p>
  
  <p>I cannot however get the editor to load at all. I am using version 4.1.9 (2015-03-10) with the jquery module.
  i.e. both tinymce.jquery.js &amp; jquery.tinymce.min.js</p>
  
  <p>Once the dialog window has opened i call this;</p>
  
  <pre><code>$("textarea").tinymce({
      // General options
      mode: "textareas",
      theme: "modern",
      // Theme options
      menubar: false,
      toolbar: "bold,italic,underline,|,bullist,numlist",
      statusbar: false,
      init_instance_callback: function (editor) {
          console.log("tinymce init: " + editor.id);
      }
  });
  </code></pre>
  
  <p>But i get an exception in the javascript in the following method, it appears self.ariaTarget is undefined leading to the line starting elm.setAttribute failing because elm is null.<br>
  I don't understand what i have done wrong.</p>
  
  <pre><code>/**
  * Sets the specified aria property.
   *
   * @method aria
   * @param {String} name Name of the aria property to set.
   * @param {String} value Value of the aria property.
   * @return {tinymce.ui.Control} Current control instance.
   */
  aria: function(name, value) {
      var self = this, elm = self.getEl(self.ariaTarget);
          if (typeof value === "undefined") {
          return self._aria[name];
      } else {
          self._aria[name] = value;
      }
          if (self._rendered) {
          elm.setAttribute(name == 'role' ? name : 'aria-' + name, value);
      }
          return self;
  },
  </code></pre>
  
  <p>Thanks for the help.<br>
  Mark</p>
  
  <p><strong>Edit:</strong><br>
  I have been following this jsfiddle <a href="http://jsfiddle.net/thomi_ch/m0aLmh3n/19/">http://jsfiddle.net/thomi_ch/m0aLmh3n/19/</a> and instead of loading tinymce in with the document, it loads it from a url when it initialises (see below). I've changed my code to use the same script_url as the example and it works to render the editor (missing icons etc as the css cant be found) but this implies to me that there is something wrong with the version of my tinymce.jquery.js file.</p>
  
  <pre><code>$('textarea').tinymce({
      script_url : 'http://demo.nilooma.com/system/plugins/tinymce/4.1.6/tiny_mce/tinymce.gzip.php',
      toolbar: 'link',
      plugins: 'link',
      forced_root_block : '',
      init_instance_callback: function(editor) {
          console.log('tinymce init: '+editor.id);
      }
  });
  </code></pre>
  
  <p>I have tried both tinymce.jquery.js &amp; tinymce.js from versions 4.1.9 &amp; 4.1.6 as the jsfiddle uses and all the combinations give me the same error.<br>
  Is it possible that there is an incompatibility with another library?</p>