diff --git a/ckeditor.html b/ckeditor.html
index 4cab0ce..e123264 100644
--- a/ckeditor.html
+++ b/ckeditor.html
@@ -13,9 +13,13 @@
     </div>
     <bes-popup-el></bes-popup-el>
     <script>
-      ClassicEditor.create(document.querySelector('#editor')).catch(error => {
-        console.error(error)
-      })
+      ClassicEditor.create(document.querySelector('#editor'))
+        .then(newEditor => {
+          BesEditor.register(newEditor.ui.view.editable.element, newEditor)
+        })
+        .catch(error => {
+          console.error(error)
+        })
     </script>
   </body>
 
diff --git a/online-editor.js b/online-editor.js
index baef5ac..1e332c7 100644
--- a/online-editor.js
+++ b/online-editor.js
@@ -11,7 +11,9 @@ class BesEditor {
     this.correctionPanel = correctionPanel
     this.scrollPanel = scrollPanel
     this.offsetTop = null
+    // TODO: consider simplfing ckeditor handling by using a single constructor parameter
     this.isCKeditor = !!isCkeditor
+    this.CKEditorInstance = isCkeditor
     edit.classList.add('bes-online-editor')
     this.originalSpellcheck = edit.spellcheck
     edit.spellcheck = false
@@ -169,7 +171,7 @@ class BesEditor {
                 })
                 this.markProofed(el, matches)
 
-                // This is a solution for CKEditor. It is not the best solution, but it works for now.
+                // This is a solution for displaying mistakes in CKEditor. It is not the best solution, but it works for now.
                 if (this.isCKeditor) {
                   const resizeEvent = new Event('resize')
                   window.dispatchEvent(resizeEvent)
@@ -283,7 +285,7 @@ class BesEditor {
     if (!child) return
     child.isProofed = false
     child.matches.forEach(match => {
-      match.highlights.forEach(h => h.remove())
+      match?.highlights.forEach(h => h.remove())
       delete match.highlights
     })
   }
@@ -487,7 +489,10 @@ class BesEditor {
    */
   static findParent(el) {
     for (; el; el = el.parentNode) {
-      if (el.classList?.contains('bes-online-editor')) {
+      if (
+        el.classList?.contains('bes-online-editor') ||
+        el.classList?.contains('ck-editor__editable') // Find a better way to handle CKEditor
+      ) {
         return el
       }
     }
@@ -503,9 +508,7 @@ class BesEditor {
    */
   renderPopup(el, clientX, clientY) {
     const popup = document.querySelector('bes-popup-el')
-    const matches = this.children.find(
-      child => child.elements === el
-    )?.matches
+    const matches = this.children.find(child => child.elements === el)?.matches
     if (matches) {
       for (let m of matches) {
         if (m.rects) {
@@ -541,6 +544,21 @@ class BesEditor {
       replacement +
       text.substring(match.offset + match.length)
     el.textContent = newText
+    if (editor.isCKeditor) {
+      const { CKEditorInstance } = editor
+      CKEditorInstance.model.change(writer => {
+        // Find the corresponding element in the model.
+        const viewElement =
+          CKEditorInstance.editing.view.domConverter.mapDomToView(el)
+        const modelElement =
+          CKEditorInstance.editing.mapper.toModelElement(viewElement)
+
+        if (modelElement) {
+          writer.remove(writer.createRangeIn(modelElement))
+          writer.insertText(newText, modelElement, 'end')
+        }
+      })
+    }
     BesEditor.clearSingleMistake(editor, el, rect)
     // In my opinion, this approach provides the most straightforward solution for repositioning mistakes after a change.
     // It maintains reasonable performance as it only checks the block element that has been modified,
@@ -615,12 +633,6 @@ window.onload = () => {
   document
     .querySelectorAll('.bes-online-editor')
     .forEach(edit => BesEditor.register(edit))
-
-  // TODO: not the most optimal solution, but it works for now
-  // Find contenteditable element inside ckeditor and prepare it
-  document.querySelectorAll('.ck-editor__editable').forEach(edit => {
-    BesEditor.register(edit, true)
-  })
 }
 
 window.onresize = () => {