diff --git a/resources/assets/javascripts/lib/wysiwyg.js b/resources/assets/javascripts/lib/wysiwyg.js
index 23314f69a0ace0550cd8e9853b2d9b91af5ac725..eacd5098c7084e385027288aba1223c287acc668 100644
--- a/resources/assets/javascripts/lib/wysiwyg.js
+++ b/resources/assets/javascripts/lib/wysiwyg.js
@@ -193,7 +193,7 @@ function replaceTextarea(textarea) {
         }
 
         // Tell MathJax v2.7 to leave the editor alone
-        ckeditor.ui.element.classList.add("tex2jax_ignore");
+        ckeditor.ui.element.classList.add('tex2jax_ignore');
 
         // TODO: Kein updateSourceElement im SourceEditing-Modus
         //     $(ckeditor.container.$).on('blur', '.CodeMirror', function (event) {