diff --git a/online-editor.js b/online-editor.js
index e8b849c..547cfda 100644
--- a/online-editor.js
+++ b/online-editor.js
@@ -1,9 +1,9 @@
 const besUrl = 'http://localhost:225/api/v2/check'
 
-let besEditors = [] // Collection of all editors on page
+let besEditors = [] // Collection of all grammar checking services in the document
 
 class BesEditor {
-  constructor(edit) {
+  constructor(edit, isCkeditor) {
     this.el = edit
     this.timer = null
     this.children = []
@@ -11,31 +11,54 @@ class BesEditor {
     this.correctionPanel = correctionPanel
     this.scrollPanel = scrollPanel
     this.offsetTop = null
-    this.isCKeditor = false
-    this.disableSpellcheck(edit)
-    this.proof(edit)
-    edit.addEventListener('beforeinput', e => this.handleBeforeInput(e), false)
-    edit.addEventListener('click', e => this.handleClick(e))
-    edit.addEventListener('scroll', e =>
-      this.handleScrollEvent(edit, this.scrollPanel)
-    )
-  }
-
-  // Register editor
-  static register(edit, isCkeditor) {
-    let editor = new BesEditor(edit)
-    besEditors.push(editor)
-    if (isCkeditor) editor.isCKeditor = true
-    return editor
-  }
-
-  // Set spellcheck to false
-  disableSpellcheck(edit) {
+    this.isCKeditor = !!isCkeditor
+    edit.classList.add('bes-online-editor')
+    this.originalSpellcheck = edit.spellcheck
     edit.spellcheck = false
+    this.proof(edit)
+    edit.addEventListener('beforeinput', BesEditor.handleBeforeInput, false)
+    edit.addEventListener('click', BesEditor.handleClick)
+    edit.addEventListener('scroll', BesEditor.handleScroll)
+    besEditors.push(this)
+  }
+
+  /**
+   * Registers grammar checking service
+   *
+   * @param {Element} edit DOM element to register grammar checking service for
+   * @param {Boolean} isCkeditor Enable CKEditor tweaks
+   * @returns {BesEditor} Grammar checking service instance
+   */
+  static register(edit, isCkeditor) {
+    return new BesEditor(edit, isCkeditor)
+  }
+
+  /**
+   * Unregisters grammar checking service
+   */
+  unregister() {
+    this.el.removeEventListener('scroll', BesEditor.handleScroll)
+    this.el.removeEventListener('click', BesEditor.handleClick)
+    this.el.removeEventListener(
+      'beforeinput',
+      BesEditor.handleBeforeInput,
+      false
+    )
+    if (this.timer) clearTimeout(this.timer)
+    besEditors = besEditors.filter(item => item !== this)
+    this.el.spellcheck = this.originalSpellcheck
+    this.el.classList.remove('bes-online-editor')
+    this.correctionPanel.remove()
+    this.scrollPanel.remove()
   }
 
   // TODO: add support for textarea elements
-  // Recursively grammar-proofs one node.
+  /**
+   * Recursively grammar-proofs a DOM tree.
+   *
+   * @param {Node} el DOM root node to proof
+   * @returns {Array} Markup of text to proof using BesStr
+   */
   async proof(el) {
     // If first child is not a block element, add a dummy <div>...</div> around it.
     // This solution is still not fully tested and might need some improvements.
@@ -196,27 +219,35 @@ class BesEditor {
     return { correctionPanel, scrollPanel }
   }
 
-  // Marks section of text that is about to change as not-yet-grammar-proofed.
-  handleBeforeInput(event) {
-    if (this.timer) clearTimeout(this.timer)
+  /**
+   * beforeinput event handler
+   *
+   * Marks section of the text that is about to change as not-yet-grammar-proofed.
+   *
+   * @param {InputEvent} event The event notifying the user of editable content changes
+   */
+  static handleBeforeInput(event) {
+    const edit = event.target
+    let editor = besEditors.find(e => e.el === edit)
+    if (!editor) return
+    if (editor.timer) clearTimeout(editor.timer)
     let blockElements = new Set()
     event.getTargetRanges().forEach(range => {
       BesEditor.getNodesInRange(range).forEach(el =>
-        blockElements.add(this.getBlockParent(el))
+        blockElements.add(editor.getBlockParent(el))
       )
     })
     blockElements.forEach(block => {
-      this.clearProofed(block)
-      this.clearMistakeMarkup(block)
-      this.clearChildren(block)
+      editor.clearProofed(block)
+      editor.clearMistakeMarkup(block)
+      editor.clearChildren(block)
     })
-    let editor = this
-    // Not the nice way to do it, but it works for now the repositionMistakes function is called before the DOM updates are finished.
+    // Not a nice way to do it, but it works for now the repositionMistakes function is called before the DOM updates are finished.
     setTimeout(() => {
-      editor.repositionMistakes(editor)
+      editor.repositionMistakes()
     }, 0)
-    this.timer = setTimeout(function () {
-      editor.proof(editor.el)
+    editor.timer = setTimeout(function () {
+      editor.proof(edit)
     }, 1000)
   }
 
@@ -230,7 +261,7 @@ class BesEditor {
   markProofed(el, matches) {
     let newChild = {
       isProofed: true,
-      elements: el,
+      elements: el, // TODO: Rename "elements" to "el" - 1. It contains only single element (plural elements is misleading), 2. BesEditor also uses "el" named field for DOM matching.
       matches: matches
     }
 
@@ -269,8 +300,8 @@ class BesEditor {
     else this.children = this.children.filter(child => child.elements !== el)
   }
 
-  repositionMistakes(editor) {
-    editor.children.forEach(child => {
+  repositionMistakes() {
+    this.children.forEach(child => {
       this.clearMistakeMarkup(child.elements)
       child.matches.forEach(match => {
         const { clientRects, highlight } = this.addMistakeMarkup(
@@ -382,60 +413,71 @@ class BesEditor {
     return nodes
   }
 
-  handleClick(e) {
-    const targetEl = e.target
+  /**
+   * click event handler
+   *
+   * Displays or hides grammar mistake popup.
+   *
+   * @param {PointerEvent} event The event produced by a pointer such as the geometry of the contact point, the device type that generated the event, the amount of pressure that was applied on the contact surface, etc.
+   */
+  static handleClick(event) {
+    const edit = BesEditor.findParent(event.target)
+    let editor = besEditors.find(e => e.el === edit)
+    if (!editor) return
+    const target = editor.getBlockParent(event.target)
     const popup = document.querySelector('bes-popup-el')
-    // If target has not parent with class 'bes-online-editor', find target's parent whose parent is 'bes-online-editor'
-    const target = BesEditor.findParent(targetEl)
-      ? BesEditor.findParent(targetEl)
-      : targetEl
-
-    const divIndex = this.children.findIndex(child => child.elements === target)
-    const matches = this.children[divIndex]?.matches
-    if (!matches) {
-      popup.hide()
-      return
-    }
+    const matches = editor.children.find(
+      child => child.elements === target
+    )?.matches
     if (
-      BesEditor.renderPopup(target, matches, popup, e.clientX, e.clientY, this)
+      !matches ||
+      !editor.renderPopup(target, matches, popup, event.clientX, event.clientY)
     )
-      return
-    else popup.hide()
+      popup.hide()
   }
 
-  handleScrollEvent(editor, scrollPanel) {
-    scrollPanel.style.top = -editor.scrollTop + 'px'
-    this.offsetTop = editor.scrollTop
+  /**
+   * scroll event handler
+   *
+   * Syncs grammar mistake positions with editor scroll offset.
+   *
+   * @param {Event} event The event which takes place.
+   */
+  static handleScroll(event) {
+    const edit = event.target
+    let editor = besEditors.find(e => e.el === edit)
+    if (!editor) return
+    editor.scrollPanel.style.top = -edit.scrollTop + 'px'
+    editor.offsetTop = edit.scrollTop
     setTimeout(() => {
-      this.repositionMistakes(this)
+      editor.repositionMistakes()
     }, 300)
+    // TODO: Move popup (if open) too.
   }
 
+  /**
+   * Finds the editor with grammar checking service the given DOM node is a child of.
+   *
+   * @param {Node} target DOM node
+   * @returns {Element} Editor DOM element; null if DOM node is not a descendant of an editor.
+   */
   static findParent(target) {
-    let element = target
-    while (element && element.parentNode) {
-      if (element.parentNode.classList?.contains('bes-online-editor')) {
-        return element
+    for (let el = target; el; el = el.parentNode) {
+      if (el.classList?.contains('bes-online-editor')) {
+        return el
       }
-      element = element.parentNode
     }
     return null
   }
 
-  static renderPopup(el, matches, popup, clientX, clientY, editor) {
+  renderPopup(el, matches, popup, clientX, clientY) {
     for (let m of matches) {
       if (m.rects) {
         for (let r of m.rects) {
           if (BesEditor.isPointInRect(clientX, clientY, r)) {
             popup.changeText(m.match.message)
             m.match.replacements.forEach(replacement => {
-              popup.appendReplacements(
-                el,
-                r,
-                m.match,
-                replacement.value,
-                editor
-              )
+              popup.appendReplacements(el, r, m.match, replacement.value, this)
             })
             popup.show(clientX, clientY)
             return true