diff --git a/src/automath.js b/src/automath.js
index d4417222e..9db75022b 100644
--- a/src/automath.js
+++ b/src/automath.js
@@ -3,6 +3,7 @@ import Clipboard from '@ckeditor/ckeditor5-clipboard/src/clipboard';
 import Undo from '@ckeditor/ckeditor5-undo/src/undo';
 import LiveRange from '@ckeditor/ckeditor5-engine/src/model/liverange';
 import LivePosition from '@ckeditor/ckeditor5-engine/src/model/liveposition';
+import global from '@ckeditor/ckeditor5-utils/src/dom/global';
 
 import { defaultConfig, extractDelimiters, hasDelimiters } from './utils';
 
@@ -46,7 +47,7 @@ export default class AutoMath extends Plugin {
 
 		editor.commands.get( 'undo' ).on( 'execute', () => {
 			if ( this._timeoutId ) {
-				global.window.clearTimeout( this._timeoutId ); // eslint-disable-line
+				global.window.clearTimeout( this._timeoutId );
 				this._positionToInsert.detach();
 
 				this._timeoutId = null;
@@ -89,7 +90,7 @@ export default class AutoMath extends Plugin {
 		this._positionToInsert = LivePosition.fromPosition( leftPosition );
 
 		// With timeout user can undo conversation if want use plain text
-		this._timeoutId = global.window.setTimeout( () => { // eslint-disable-line
+		this._timeoutId = global.window.setTimeout( () => {
 			editor.model.change( writer => {
 				this._timeoutId = null;
 
diff --git a/src/mathui.js b/src/mathui.js
index 8984eba8a..e78c35ee4 100644
--- a/src/mathui.js
+++ b/src/mathui.js
@@ -3,6 +3,7 @@ import ClickObserver from '@ckeditor/ckeditor5-engine/src/view/observer/clickobs
 import ContextualBalloon from '@ckeditor/ckeditor5-ui/src/panel/balloon/contextualballoon';
 import clickOutsideHandler from '@ckeditor/ckeditor5-ui/src/bindings/clickoutsidehandler';
 import uid from '@ckeditor/ckeditor5-utils/src/uid';
+import global from '@ckeditor/ckeditor5-utils/src/dom/global';
 
 import ButtonView from '@ckeditor/ckeditor5-ui/src/button/buttonview';
 import MainFormView from './ui/mainformview';
@@ -11,7 +12,7 @@ import MainFormView from './ui/mainformview';
 import MathEditing from './mathediting';
 import { defaultConfig } from './utils';
 
-import pluginIcon from '../theme/icons/icon.svg';
+import mathIcon from '../theme/icons/math.svg';
 
 const mathKeystroke = 'Ctrl+M';
 
@@ -30,7 +31,7 @@ export default class MathUI extends Plugin {
 
 		this._previewUid = `math-preview-${ uid() }`;
 
-		this._form = this._createFormView();
+		this.formView = this._createFormView();
 
 		this._balloon = editor.plugins.get( ContextualBalloon );
 
@@ -42,10 +43,10 @@ export default class MathUI extends Plugin {
 	destroy() {
 		super.destroy();
 
-		this._form.destroy();
+		this.formView.destroy();
 
 		// Destroy preview element
-		let prewviewEl = document.getElementById( this._previewUid ); // eslint-disable-line
+		const prewviewEl = global.document.getElementById( this._previewUid );
 		if ( prewviewEl ) {
 			prewviewEl.parentNode.removeChild( prewviewEl );
 		}
@@ -104,23 +105,23 @@ export default class MathUI extends Plugin {
 		const mathCommand = editor.commands.get( 'math' );
 
 		this._balloon.add( {
-			view: this._form,
+			view: this.formView,
 			position: this._getBalloonPositionData(),
 		} );
 
-		if ( this._balloon.visibleView === this._form ) {
-			this._form.mathInputView.select();
+		if ( this._balloon.visibleView === this.formView ) {
+			this.formView.mathInputView.select();
 		}
 
 		// Show preview element
-		let prewviewEl = document.getElementById( this._previewUid ); // eslint-disable-line
-		if ( prewviewEl && this._form.previewEnabled ) {
+		const prewviewEl = global.document.getElementById( this._previewUid );
+		if ( prewviewEl && this.formView.previewEnabled ) {
 			// Force refresh preview
-			this._form.mathView.updateMath();
+			this.formView.mathView.updateMath();
 		}
 
-		this._form.equation = mathCommand.value || '';
-		this._form.displayButtonView.isOn = mathCommand.display || false;
+		this.formView.equation = mathCommand.value || '';
+		this.formView.displayButtonView.isOn = mathCommand.display || false;
 	}
 
 	_hideUI() {
@@ -150,12 +151,12 @@ export default class MathUI extends Plugin {
 
 	_removeFormView() {
 		if ( this._isFormInPanel ) {
-			this._form.saveButtonView.focus();
+			this.formView.saveButtonView.focus();
 
-			this._balloon.remove( this._form );
+			this._balloon.remove( this.formView );
 
 			// Hide preview element
-			let prewviewEl = document.getElementById( this._previewUid );// eslint-disable-line
+			const prewviewEl = global.document.getElementById( this._previewUid );
 			if ( prewviewEl ) {
 				prewviewEl.style.visibility = 'hidden';
 			}
@@ -191,7 +192,7 @@ export default class MathUI extends Plugin {
 
 			button.isEnabled = true;
 			button.label = t( 'Insert math' );
-			button.icon = pluginIcon;
+			button.icon = mathIcon;
 			button.keystroke = mathKeystroke;
 			button.tooltip = true;
 			button.isToggleable = true;
@@ -215,7 +216,7 @@ export default class MathUI extends Plugin {
 
 		// Close on click outside of balloon panel element.
 		clickOutsideHandler( {
-			emitter: this._form,
+			emitter: this.formView,
 			activator: () => this._isFormInPanel,
 			contextElements: [ this._balloon.view.element ],
 			callback: () => this._hideUI()
@@ -225,10 +226,10 @@ export default class MathUI extends Plugin {
 	get _isUIVisible() {
 		const visibleView = this._balloon.visibleView;
 
-		return visibleView == this._form;
+		return visibleView == this.formView;
 	}
 
 	get _isFormInPanel() {
-		return this._balloon.hasView( this._form );
+		return this._balloon.hasView( this.formView );
 	}
 }
diff --git a/src/utils.js b/src/utils.js
index 9491afc71..cd402e131 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -1,3 +1,7 @@
+/* globals MathJax, katex, console */
+
+import global from '@ckeditor/ckeditor5-utils/src/dom/global';
+
 export const defaultConfig = {
 	engine: 'mathjax',
 	outputType: 'script',
@@ -56,8 +60,7 @@ export function renderEquation( equation, element, engine = 'katex', display = f
 		} else {
 			selectRenderMode( element, preview, previewUid, el => {
 				// Fixme: MathJax typesetting cause occasionally math processing error without asynchronous call
-				// eslint-disable-next-line
-				setTimeout( () => {
+				global.window.setTimeout( () => {
 					renderMathJax2( equation, el, display );
 
 					// Move and scale after rendering
@@ -86,8 +89,7 @@ export function renderEquation( equation, element, engine = 'katex', display = f
 		engine( equation, element, display );
 	} else {
 		element.innerHTML = equation;
-		// eslint-disable-next-line
-		console.warn( `math-tex-typesetting-missing: Missing the mathematical typesetting engine (${engine}) for tex.` );
+		console.warn( `math-tex-typesetting-missing: Missing the mathematical typesetting engine (${ engine }) for tex.` );
 	}
 }
 
@@ -126,7 +128,8 @@ function renderMathJax2( equation, element, display ) {
 	} else {
 		element.innerHTML = '\\(' + equation + '\\)';
 	}
-	MathJax.Hub.Queue( [ 'Typeset', MathJax.Hub, element ] ); // eslint-disable-line
+	// eslint-disable-next-line
+	MathJax.Hub.Queue( [ 'Typeset', MathJax.Hub, element ] );
 }
 
 function createPreviewElement( element, previewUid, render ) {
@@ -135,20 +138,19 @@ function createPreviewElement( element, previewUid, render ) {
 }
 
 function getPreviewElement( element, previewUid ) {
-	let prewviewEl = document.getElementById( previewUid ); // eslint-disable-line
+	let prewviewEl = global.document.getElementById( previewUid );
 	// Create if not found
 	if ( !prewviewEl ) {
-		prewviewEl = document.createElement( 'div' ); // eslint-disable-line
+		prewviewEl = global.document.createElement( 'div' );
 		prewviewEl.setAttribute( 'id', previewUid );
 		prewviewEl.style.visibility = 'hidden';
-		document.body.appendChild( prewviewEl ); // eslint-disable-line
+		global.document.body.appendChild( prewviewEl );
 
 		let ticking = false;
 
 		const renderTransformation = () => {
 			if ( !ticking ) {
-				// eslint-disable-next-line
-				window.requestAnimationFrame( () => {
+				global.window.requestAnimationFrame( () => {
 					moveElement( element, prewviewEl );
 					ticking = false;
 				} );
@@ -158,8 +160,8 @@ function getPreviewElement( element, previewUid ) {
 		};
 
 		// Create scroll listener for following
-		window.addEventListener( 'resize', renderTransformation ); // eslint-disable-line
-		window.addEventListener( 'scroll', renderTransformation ); // eslint-disable-line
+		global.window.addEventListener( 'resize', renderTransformation );
+		global.window.addEventListener( 'scroll', renderTransformation );
 	}
 	return prewviewEl;
 }
@@ -176,8 +178,8 @@ function moveAndScaleElement( parent, child ) {
 
 function moveElement( parent, child ) {
 	const domRect = parent.getBoundingClientRect();
-	const left = window.scrollX + domRect.left; // eslint-disable-line
-	const top = window.scrollY + domRect.top; // eslint-disable-line
+	const left = global.window.scrollX + domRect.left;
+	const top = global.window.scrollY + domRect.top;
 	child.style.position = 'absolute';
 	child.style.left = left + 'px';
 	child.style.top = top + 'px';
diff --git a/theme/icons/icon.svg b/theme/icons/math.svg
similarity index 100%
rename from theme/icons/icon.svg
rename to theme/icons/math.svg