diff --git a/resources/assets/js/components/wysiwyg-editor.js b/resources/assets/js/components/wysiwyg-editor.js
index 614cfb80f..eb9f025a7 100644
--- a/resources/assets/js/components/wysiwyg-editor.js
+++ b/resources/assets/js/components/wysiwyg-editor.js
@@ -168,23 +168,24 @@ function codePlugin() {
         });
     }
 
-    function codeMirrorContainerToPre($codeMirrorContainer) {
-        let textArea = $codeMirrorContainer[0].querySelector('textarea');
-        let code = textArea.textContent;
-        let lang = $codeMirrorContainer[0].getAttribute('data-lang');
+    function codeMirrorContainerToPre(codeMirrorContainer) {
+        const textArea = codeMirrorContainer.querySelector('textarea');
+        const code = textArea.textContent;
+        const lang = codeMirrorContainer.getAttribute('data-lang');
 
-        $codeMirrorContainer.removeAttr('contentEditable');
-        let $pre = $('<pre></pre>');
-        $pre.append($('<code></code>').each((index, elem) => {
-            // Needs to be textContent since innerText produces BR:s
-            elem.textContent = code;
-        }).attr('class', `language-${lang}`));
-        $codeMirrorContainer.replaceWith($pre);
+        codeMirrorContainer.removeAttribute('contentEditable');
+        const pre = document.createElement('pre');
+        const codeElem = document.createElement('code');
+        codeElem.classList.add(`language-${lang}`);
+        codeElem.textContent = code;
+        pre.appendChild(codeElem);
+
+        codeMirrorContainer.parentElement.replaceChild(pre, codeMirrorContainer);
     }
 
     window.tinymce.PluginManager.add('codeeditor', function(editor, url) {
 
-        let $ = editor.$;
+        const $ = editor.$;
 
         editor.addButton('codeeditor', {
             text: 'Code block',
@@ -198,10 +199,8 @@ function codePlugin() {
 
         // Convert
         editor.on('PreProcess', function (e) {
-            $('div.CodeMirrorContainer', e.node).
-            each((index, elem) => {
-                let $elem = $(elem);
-                codeMirrorContainerToPre($elem);
+            $('div.CodeMirrorContainer', e.node).each((index, elem) => {
+                codeMirrorContainerToPre(elem);
             });
         });
 
@@ -217,10 +216,10 @@ function codePlugin() {
             $('.CodeMirrorContainer').filter((index ,elem) => {
                 return typeof elem.querySelector('.CodeMirror').CodeMirror === 'undefined';
             }).each((index, elem) => {
-                codeMirrorContainerToPre($(elem));
+                codeMirrorContainerToPre(elem);
             });
 
-            let codeSamples = $('body > pre').filter((index, elem) => {
+            const codeSamples = $('body > pre').filter((index, elem) => {
                 return elem.contentEditable !== "false";
             });
 
@@ -341,7 +340,7 @@ function drawIoPlugin() {
         });
 
         editor.on('SetContent', function () {
-            let drawings = editor.$('body > div[drawio-diagram]');
+            const drawings = editor.$('body > div[drawio-diagram]');
             if (!drawings.length) return;
 
             editor.undoManager.transact(function () {
@@ -472,9 +471,10 @@ class WysiwygEditor {
 
                 if (type === 'file') {
                     window.EntitySelectorPopup.show(function(entity) {
-                        let originalField = win.document.getElementById(field_name);
+                        const originalField = win.document.getElementById(field_name);
                         originalField.value = entity.link;
-                        $(originalField).closest('.mce-form').find('input').eq(2).val(entity.name);
+                        const mceForm = originalField.closest('.mce-form');
+                        mceForm.querySelectorAll('input')[2].value = entity.name;
                     });
                 }