diff --git a/ckeditor.html b/ckeditor.html
index 35b6fda..9692128 100644
--- a/ckeditor.html
+++ b/ckeditor.html
@@ -15,7 +15,7 @@
     <script>
       ClassicEditor.create(document.querySelector('#editor'))
         .then(newEditor => {
-          BesService.register(newEditor.ui.view.editable.element, newEditor)
+          BesCKService.register(newEditor.ui.view.editable.element, newEditor)
         })
         .catch(error => {
           console.error(error)
diff --git a/service.js b/service.js
index 556f150..ff66d87 100644
--- a/service.js
+++ b/service.js
@@ -4,21 +4,27 @@ let besServices = [] // Collection of all grammar checking services in the docum
 
 // TODO: Add support for <textarea>
 
+///
+/// Grammar checking service base class
+///
 class BesService {
-  constructor(hostElement, ckEditorInstance) {
+  constructor(hostElement) {
     this.hostElement = hostElement
     this.timer = null
     this.children = []
-    const { correctionPanel, scrollPanel } = this.createCorrectionPanel(hostElement)
+    const { correctionPanel, scrollPanel } =
+      this.createCorrectionPanel(hostElement)
     this.correctionPanel = correctionPanel
     this.scrollPanel = scrollPanel
     this.offsetTop = null
-    this.ckEditorInstance = ckEditorInstance
     this.originalSpellcheck = hostElement.spellcheck
-    hostElement.spellcheck = false
     this.abortController = new AbortController()
-    this.proof(hostElement)
-    hostElement.addEventListener('beforeinput', BesService.handleBeforeInput, false)
+    hostElement.spellcheck = false
+    hostElement.addEventListener(
+      'beforeinput',
+      BesService.handleBeforeInput,
+      false
+    )
     hostElement.addEventListener('click', BesService.handleClick)
     hostElement.addEventListener('scroll', BesService.handleScroll)
     besServices.push(this)
@@ -28,11 +34,12 @@ class BesService {
    * Registers grammar checking service
    *
    * @param {Element} hostElement DOM element to register grammar checking service for
-   * @param {CKEditorInstance} ckEditorInstance Enable CKEditor tweaks
    * @returns {BesService} Grammar checking service instance
    */
-  static register(hostElement, ckEditorInstance) {
-    return new BesService(hostElement, ckEditorInstance)
+  static register(hostElement) {
+    let service = new BesService(hostElement)
+    service.proof(hostElement)
+    return service
   }
 
   /**
@@ -47,6 +54,7 @@ class BesService {
       false
     )
     if (this.timer) clearTimeout(this.timer)
+    service.abortController.abort()
     besServices = besServices.filter(item => item !== this)
     this.hostElement.spellcheck = this.originalSpellcheck
     this.correctionPanel.remove()
@@ -255,9 +263,6 @@ class BesService {
       element: el,
       matches: matches
     })
-
-    // This is a solution for displaying mistakes in CKEditor. It is not the best solution, but it works for now.
-    if (this.ckEditorInstance) window.dispatchEvent(new Event('resize'))
   }
 
   /**
@@ -307,7 +312,6 @@ class BesService {
    * @returns {Object} Client rectangles and grammar mistake highlight elements
    */
   addMistakeMarkup(range) {
-    // In CKEditor case, the highlight element is not shown for some reason. But after resizing the window it is shown.
     const clientRects = range.getClientRects()
     const scrollPanelRect = this.scrollPanel.getBoundingClientRect()
     let highlights = []
@@ -521,36 +525,8 @@ class BesService {
   replaceText(el, match, replacement) {
     if (this.timer) clearTimeout(this.timer)
     this.abortController.abort()
-    // const tags = this.getTagsAndText(el)
-    if (!this.ckEditorInstance) {
-      match.range.deleteContents()
-      match.range.insertNode(document.createTextNode(replacement))
-    } else {
-      const { ckEditorInstance } = this
-      ckEditorInstance.model.change(writer => {
-        const viewElement =
-          ckEditorInstance.editing.view.domConverter.mapDomToView(el)
-        const modelElement =
-          ckEditorInstance.editing.mapper.toModelElement(viewElement)
-        if (modelElement) {
-          const elementRange = writer.createRangeIn(modelElement)
-          // TODO: This logic should work once the HTML tags are removed from match.match.offset and match.match.length if is possible.
-          if (
-            elementRange.start.offset <= match.match.offset &&
-            elementRange.end.offset >= match.match.offset + match.match.length
-          ) {
-            const start = writer.createPositionAt(modelElement, match.match.offset)
-            const end = writer.createPositionAt(
-              modelElement,
-              match.match.offset + match.match.length
-            )
-            const range = writer.createRange(start, end)
-            writer.remove(range)
-            writer.insertText(replacement, start)
-          }
-        }
-      })
-    }
+    match.range.deleteContents()
+    match.range.insertNode(document.createTextNode(replacement))
     this.clearMistakeMarkup(el)
     // 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,
@@ -588,31 +564,108 @@ class BesService {
   }
 }
 
-window.onload = () => {
-  document
-    .querySelectorAll('.bes-service')
-    .forEach(hostElement => BesService.register(hostElement))
-}
+///
+/// Grammar checking service for CKEditor
+///
+class BesCKService extends BesService {
+  constructor(hostElement, ckEditorInstance) {
+    super(hostElement)
+    this.ckEditorInstance = ckEditorInstance
+  }
 
-window.onresize = () => {
-  besServices.forEach(service => {
-    service.setCorrectionPanelSize(
-      service.hostElement,
-      service.correctionPanel,
-      service.scrollPanel
-    )
-    service.children.forEach(child => {
-      service.clearMistakeMarkup(child.element)
+  /**
+   * Registers grammar checking service
+   *
+   * @param {Element} hostElement DOM element to register grammar checking service for
+   * @param {CKEditorInstance} ckEditorInstance Enable CKEditor tweaks
+   * @returns {BesCKService} Grammar checking service instance
+   */
+  static register(hostElement, ckEditorInstance) {
+    let service = new BesCKService(hostElement, ckEditorInstance)
+    service.proof(hostElement)
+    return service
+  }
+
+  /**
+   * Marks given block element as grammar-proofed.
+   *
+   * @param {Element} el DOM element that was checked
+   * @param {Array} matches Grammar mistakes
+   */
+  markProofed(el, matches) {
+    super.markProofed(el, matches)
+
+    // This is a solution for displaying mistakes in CKEditor. It is not the best solution, but it works for now.
+    if (this.ckEditorInstance) window.dispatchEvent(new Event('resize'))
+  }
+
+  /**
+   * Removes given block element from this.children array
+   *
+   * @param {Element} el DOM element for removal
+   */
+  removeChild(el) {
+    this.children = this.children.filter(child => child.element !== el)
+  }
+
+  /**
+   * Updates grammar mistake markup positions.
+   */
+  repositionMistakes() {
+    this.children.forEach(child => {
+      this.clearMistakeMarkup(child.element)
       child.matches.forEach(match => {
-        const { clientRects, highlights } = service.addMistakeMarkup(match.range)
+        const { clientRects, highlights } = this.addMistakeMarkup(match.range)
         match.rects = clientRects
         match.highlights = highlights
       })
     })
-  })
+  }
+
+  // TODO: In rich HTML texts, match.offset has different value than in plain text.
+  // This function should be able to handle both cases or find a way that works for both.
+  replaceText(el, match, replacement) {
+    if (this.timer) clearTimeout(this.timer)
+    this.abortController.abort()
+    const { ckEditorInstance } = this
+    ckEditorInstance.model.change(writer => {
+      const viewElement =
+        ckEditorInstance.editing.view.domConverter.mapDomToView(el)
+      const modelElement =
+        ckEditorInstance.editing.mapper.toModelElement(viewElement)
+      if (modelElement) {
+        const elementRange = writer.createRangeIn(modelElement)
+        // TODO: This logic should work once the HTML tags are removed from match.match.offset and match.match.length if is possible.
+        if (
+          elementRange.start.offset <= match.match.offset &&
+          elementRange.end.offset >= match.match.offset + match.match.length
+        ) {
+          const start = writer.createPositionAt(
+            modelElement,
+            match.match.offset
+          )
+          const end = writer.createPositionAt(
+            modelElement,
+            match.match.offset + match.match.length
+          )
+          const range = writer.createRange(start, end)
+          writer.remove(range)
+          writer.insertText(replacement, start)
+        }
+      }
+    })
+    this.clearMistakeMarkup(el)
+    // 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,
+    // rather than re-evaluating the entire document or a larger set of elements.
+    this.abortController = new AbortController()
+    this.proof(el)
+  }
 }
 
-// This is popup element
+///
+/// Grammar mistake popup dialog
+///
 class BesPopupEl extends HTMLElement {
   constructor() {
     super()
@@ -731,12 +784,37 @@ class BesPopupEl extends HTMLElement {
     replacementBtn.textContent = replacement
     replacementBtn.classList.add('bes-replacement')
     replacementBtn.addEventListener('click', () => {
-      if (allowReplacements)
-        service.replaceText(el, match, replacement)
+      if (allowReplacements) service.replaceText(el, match, replacement)
       // TODO: Close popup
     })
     replacementDiv.appendChild(replacementBtn)
   }
 }
 
+window.onload = () => {
+  document
+    .querySelectorAll('.bes-service')
+    .forEach(hostElement => BesService.register(hostElement))
+}
+
+window.onresize = () => {
+  besServices.forEach(service => {
+    service.setCorrectionPanelSize(
+      service.hostElement,
+      service.correctionPanel,
+      service.scrollPanel
+    )
+    service.children.forEach(child => {
+      service.clearMistakeMarkup(child.element)
+      child.matches.forEach(match => {
+        const { clientRects, highlights } = service.addMistakeMarkup(
+          match.range
+        )
+        match.rects = clientRects
+        match.highlights = highlights
+      })
+    })
+  })
+}
+
 customElements.define('bes-popup-el', BesPopupEl)