title: Wordpress Post/Page Editor not Working - Cannot Read Property Error
body: <p>We have a few sites using <code>Wordpress 4.9.6</code>. When trying to edit/add a post or page I see this:</p>
  
  <p><a href="https://i.stack.imgur.com/3mNr7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3mNr7.png" alt="WordPress Post Editor - Blank"></a></p>
  
  <p>And then upon inspecting the console, everything seems normal. However, when I click on the <code>text</code> button to try the text editor, this error appears in the console:</p>
  
  <pre><code>Uncaught TypeError: Cannot read property 'getSelection' of undefined
      at q (load-scripts.php?c=0&amp;load[]=hoverIntent,common,admin-bar,heartbeat,autosave,wp-ajax-response,jquery-color,wp-lists,quicktags,jquery-query,admin-comments,sug&amp;load[]=gest,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,postbox,jquery-ui-position,jquery-ui-menu,wp-a11y,jquery&amp;load[]=-ui-autocomplete,tags-suggest,tags-box,underscore,word-count,post,editor-expand,thickbox,shortcode,backbone,wp-util,wp-backbone,&amp;load[]=media-models,wp-plupload,wp-mediaelement,wp-api-request,media-views,media-editor,media-audiovideo,mce-view,imgareaselect,image-e&amp;load[]=dit,svg-painter,wp-auth-check,editor,wplink,media-upload,wp-embed&amp;ver=4.9.6:716)
      at e (load-scripts.php?c=0&amp;load[]=hoverIntent,common,admin-bar,heartbeat,autosave,wp-ajax-response,jquery-color,wp-lists,quicktags,jquery-query,admin-comments,sug&amp;load[]=gest,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,postbox,jquery-ui-position,jquery-ui-menu,wp-a11y,jquery&amp;load[]=-ui-autocomplete,tags-suggest,tags-box,underscore,word-count,post,editor-expand,thickbox,shortcode,backbone,wp-util,wp-backbone,&amp;load[]=media-models,wp-plupload,wp-mediaelement,wp-api-request,media-views,media-editor,media-audiovideo,mce-view,imgareaselect,image-e&amp;load[]=dit,svg-painter,wp-auth-check,editor,wplink,media-upload,wp-embed&amp;ver=4.9.6:716)
      at HTMLDocument.&lt;anonymous&gt; (load-scripts.php?c=0&amp;load[]=hoverIntent,common,admin-bar,heartbeat,autosave,wp-ajax-response,jquery-color,wp-lists,quicktags,jquery-query,admin-comments,sug&amp;load[]=gest,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,postbox,jquery-ui-position,jquery-ui-menu,wp-a11y,jquery&amp;load[]=-ui-autocomplete,tags-suggest,tags-box,underscore,word-count,post,editor-expand,thickbox,shortcode,backbone,wp-util,wp-backbone,&amp;load[]=media-models,wp-plupload,wp-mediaelement,wp-api-request,media-views,media-editor,media-audiovideo,mce-view,imgareaselect,image-e&amp;load[]=dit,svg-painter,wp-auth-check,editor,wplink,media-upload,wp-embed&amp;ver=4.9.6:716)
      at C (tinymce.min.js?ver=4711-20180425:2)
      at HTMLDocument.d (tinymce.min.js?ver=4711-20180425:2)
  </code></pre>
  
  <p>This site has NO plugins, and I have tried the only suggested solution I can find, of adding:</p>
  
  <pre><code>define('CONCATENATE_SCRIPTS', false);
  </code></pre>
  
  <p>to our wp-config.php file.</p>
  
  <p>There is a script not loading on the post edit pages if you look on the network tab:</p>
  
  <pre><code>http://search.rocketfacts.com/wp-includes/js/tinymce/themes/modern/theme.min.js?wp-mce-4711-20180425
  </code></pre>