diff --git a/src/components/main.jsx b/src/components/main.jsx
index 5b4d7cc59..e9a097dc8 100644
--- a/src/components/main.jsx
+++ b/src/components/main.jsx
@@ -101,12 +101,12 @@ class UI extends React.Component {
 		// debounce it, when the handler is being invoked, the target might be no more part
 		// of the editor's UI - onActionPerformed causes re-render.
 
-		this._mousedownListener = event => {
+		this._mousedownListener = (event) => {
 			this._setUIHidden(event.target);
 		};
 
 		this._keyDownListener = CKEDITOR.tools.debounce(
-			_event => {
+			(_event) => {
 				this._setUIHidden(document.activeElement);
 			},
 			this.props.eventsDelay,
@@ -201,7 +201,7 @@ class UI extends React.Component {
 		} else {
 			const toolbarNames = Array.prototype.slice
 				.call(toolbarsNodeList)
-				.map(toolbar => {
+				.map((toolbar) => {
 					return toolbar.getAttribute('aria-label');
 				});
 
@@ -229,7 +229,10 @@ class UI extends React.Component {
 		}
 
 		if (this._keyDownListener) {
-			this._keyDownListener.detach();
+			if (this._keyDownListener.detach) {
+				this._keyDownListener.detach();
+			}
+
 			document.removeEventListener('keydown', this._keyDownListener);
 		}
 	}
@@ -248,11 +251,11 @@ class UI extends React.Component {
 			return null;
 		}
 
-		let toolbars = Object.keys(this.props.toolbars).map(toolbar => {
+		let toolbars = Object.keys(this.props.toolbars).map((toolbar) => {
 			return AlloyEditor.Toolbars[toolbar] || window[toolbar];
 		});
 
-		toolbars = this.filterExclusive(toolbars).map(toolbar => {
+		toolbars = this.filterExclusive(toolbars).map((toolbar) => {
 			const props = this.mergeExclusiveProps(
 				{
 					config: this.props.toolbars[toolbar.key],
diff --git a/src/core/uicore.js b/src/core/uicore.js
index 9fac979de..afa3e1c72 100644
--- a/src/core/uicore.js
+++ b/src/core/uicore.js
@@ -76,7 +76,7 @@ if (!CKEDITOR.plugins.get('ae_uicore')) {
 				? editor.config.uicore.timeout
 				: 50;
 
-			const handleUI = CKEDITOR.tools.debounce(event => {
+			const handleUI = CKEDITOR.tools.debounce((event) => {
 				ariaState = [];
 
 				if (
@@ -95,11 +95,11 @@ if (!CKEDITOR.plugins.get('ae_uicore')) {
 				}
 			}, uiTasksTimeout);
 
-			const handleAria = CKEDITOR.tools.debounce(_event => {
+			const handleAria = CKEDITOR.tools.debounce((_event) => {
 				ariaElement.innerHTML = ariaState.join('. ');
 			}, uiTasksTimeout);
 
-			const handleMouseLeave = CKEDITOR.tools.debounce(event => {
+			const handleMouseLeave = CKEDITOR.tools.debounce((event) => {
 				const aeUINodes = document.querySelectorAll('.ae-ui');
 
 				let found;
@@ -116,7 +116,7 @@ if (!CKEDITOR.plugins.get('ae_uicore')) {
 				}
 			}, uiTasksTimeout);
 
-			editor.on('ariaUpdate', event => {
+			editor.on('ariaUpdate', (event) => {
 				// handleAria is debounced function, so if it is being called multiple times, it will
 				// be canceled until some time passes.
 				// For that reason here we explicitly append the current message to the list of messages
@@ -134,7 +134,7 @@ if (!CKEDITOR.plugins.get('ae_uicore')) {
 				const focusHandler = editable.attachListener(
 					editable,
 					'focus',
-					event => {
+					(event) => {
 						focusHandler.removeListener();
 
 						editable.attachListener(editable, 'keyup', handleUI);
@@ -150,10 +150,12 @@ if (!CKEDITOR.plugins.get('ae_uicore')) {
 				);
 			});
 
-			editor.on('destroy', _event => {
+			editor.on('destroy', (_event) => {
 				ariaElement.parentNode.removeChild(ariaElement);
 
-				handleUI.detach();
+				if (handleUI.detach) {
+					handleUI.detach();
+				}
 			});
 		},