diff --git a/packages/ckeditor5-core/src/editor/editorui.js b/packages/ckeditor5-core/src/editor/editorui.js
index 874680c8976..49d6a9aba3f 100644
--- a/packages/ckeditor5-core/src/editor/editorui.js
+++ b/packages/ckeditor5-core/src/editor/editorui.js
@@ -57,7 +57,7 @@ export default class EditorUI {
 		 *
 		 * @observable
 		 */
-		this.set( 'viewportOffset', this._viewportTopOffset );
+		this.set( 'viewportOffset', this._viewportOffset );
 
 		/**
 		 * Stores all editable elements used by the editor instance.
@@ -179,12 +179,14 @@ export default class EditorUI {
 	}
 
 	/**
-	 * TODO
+	 * Returns viewport offsets object
+	 * { top: Number, right: Number, bottom: Number, left: Number }
+	 * Only top property is currently supported
 	 *
 	 * @private
-	 * @return Object
+	 * @return {Object}
 	 */
-	get _viewportTopOffset() {
+	get _viewportOffset() {
 		const editor = this.editor;
 		const viewportOffsetConfig = editor.config.get( 'ui.viewportOffset' );
 
@@ -197,12 +199,14 @@ export default class EditorUI {
 		// Fall back to deprecated toolbar config
 		if ( legacyOffsetConfig ) {
 			/**
-			 * TODO
+			 * The {@link module:core/editor/editorconfig~EditorConfig#toolbar `EditorConfig#toolbar.viewportTopOffset`}
+			 * property has been deprecated and will be removed in the near future. Please use
+			 * {@link module:core/editor/editorconfig~EditorConfig#ui `EditorConfig#ui.viewportOffset`} instead.
 			 *
-			 * @error todo-error-name
+			 * @error editor-ui-deprecated-viewport-offset-config
 			 */
 			console.warn(
-				'todo-error-name: ' +
+				'editor-ui-deprecated-viewport-offset-config: ' +
 				'The `toolbar.vieportTopOffset` configuration option is deprecated. ' +
 				'It will be removed from future CKEditor versions. Use `ui.viewportOffset.top` instead.'
 			);
diff --git a/packages/ckeditor5-editor-classic/tests/classiceditorui.js b/packages/ckeditor5-editor-classic/tests/classiceditorui.js
index f2a17d4dd89..fbf486aca61 100644
--- a/packages/ckeditor5-editor-classic/tests/classiceditorui.js
+++ b/packages/ckeditor5-editor-classic/tests/classiceditorui.js
@@ -86,7 +86,7 @@ describe( 'ClassicEditorUI', () => {
 			} );
 
 			it( 'sets view.stickyPanel#viewportTopOffset, if legacy toolbar.vierportTopOffset specified', () => {
-				sinon.stub( console, 'warn' );
+				const spy = sinon.stub( console, 'warn' );
 
 				return VirtualClassicTestEditor
 					.create( 'foo', {
@@ -95,7 +95,9 @@ describe( 'ClassicEditorUI', () => {
 						}
 					} )
 					.then( editor => {
+						expect( editor.ui.viewportOffset.top ).to.equal( 100 );
 						expect( editor.ui.view.stickyPanel.viewportTopOffset ).to.equal( 100 );
+						sinon.assert.calledOnce( spy );
 
 						return editor.destroy();
 					} );
diff --git a/packages/ckeditor5-editor-inline/tests/inlineeditorui.js b/packages/ckeditor5-editor-inline/tests/inlineeditorui.js
index be5f0c00955..b5e654a9da9 100644
--- a/packages/ckeditor5-editor-inline/tests/inlineeditorui.js
+++ b/packages/ckeditor5-editor-inline/tests/inlineeditorui.js
@@ -85,7 +85,7 @@ describe( 'InlineEditorUI', () => {
 			} );
 
 			it( 'sets view#viewportTopOffset, if legacy toolbar.vierportTopOffset specified', () => {
-				sinon.stub( console, 'warn' );
+				const spy = sinon.stub( console, 'warn' );
 
 				return VirtualInlineTestEditor
 					.create( 'foo', {
@@ -95,9 +95,10 @@ describe( 'InlineEditorUI', () => {
 					} )
 					.then( editor => {
 						const ui = editor.ui;
-						const view = ui.view;
 
-						expect( view.viewportTopOffset ).to.equal( 100 );
+						expect( ui.viewportOffset.top ).to.equal( 100 );
+						expect( ui.view.viewportTopOffset ).to.equal( 100 );
+						sinon.assert.calledOnce( spy );
 
 						return editor.destroy();
 					} );
diff --git a/packages/ckeditor5-ui/tests/toolbar/normalizetoolbarconfig.js b/packages/ckeditor5-ui/tests/toolbar/normalizetoolbarconfig.js
index 36f1b91a345..72db3fc89a2 100644
--- a/packages/ckeditor5-ui/tests/toolbar/normalizetoolbarconfig.js
+++ b/packages/ckeditor5-ui/tests/toolbar/normalizetoolbarconfig.js
@@ -3,8 +3,6 @@
  * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
  */
 
-/* globals console */
-
 import normalizeToolbarConfig from '../../src/toolbar/normalizetoolbarconfig';
 
 describe( 'normalizeToolbarConfig()', () => {
@@ -55,15 +53,4 @@ describe( 'normalizeToolbarConfig()', () => {
 		expect( normalized.items ).to.be.an( 'array' ).of.length( 0 );
 		expect( normalized.removeItems ).to.be.an( 'array' ).of.length( 0 );
 	} );
-
-	it( 'warns when deprecated viewportTopOffset config property is used', () => {
-		const spy = sinon.stub( console, 'warn' );
-
-		const cfg = {
-			viewportTopOffset: 100
-		};
-
-		normalizeToolbarConfig( cfg );
-		sinon.assert.calledOnce( spy );
-	} );
 } );