diff --git a/extensions/html-language-features/client/src/tagClosing.ts b/extensions/html-language-features/client/src/tagClosing.ts
index 0b0b7b2114f..a05360ecc3b 100644
--- a/extensions/html-language-features/client/src/tagClosing.ts
+++ b/extensions/html-language-features/client/src/tagClosing.ts
@@ -3,13 +3,13 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { window, workspace, Disposable, TextDocumentContentChangeEvent, TextDocument, Position, SnippetString } from 'vscode';
+import { window, workspace, Disposable, TextDocument, Position, SnippetString, TextDocumentChangeEvent, TextDocumentChangeReason } from 'vscode';
 import { Runtime } from './htmlClient';
 
 export function activateTagClosing(tagProvider: (document: TextDocument, position: Position) => Thenable<string>, supportedLanguages: { [id: string]: boolean }, configName: string, runtime: Runtime): Disposable {
 
-	let disposables: Disposable[] = [];
-	workspace.onDidChangeTextDocument(event => onDidChangeTextDocument(event.document, event.contentChanges), null, disposables);
+	const disposables: Disposable[] = [];
+	workspace.onDidChangeTextDocument(onDidChangeTextDocument, null, disposables);
 
 	let isEnabled = false;
 	updateEnabledState();
@@ -25,11 +25,11 @@ export function activateTagClosing(tagProvider: (document: TextDocument, positio
 
 	function updateEnabledState() {
 		isEnabled = false;
-		let editor = window.activeTextEditor;
+		const editor = window.activeTextEditor;
 		if (!editor) {
 			return;
 		}
-		let document = editor.document;
+		const document = editor.document;
 		if (!supportedLanguages[document.languageId]) {
 			return;
 		}
@@ -39,33 +39,34 @@ export function activateTagClosing(tagProvider: (document: TextDocument, positio
 		isEnabled = true;
 	}
 
-	function onDidChangeTextDocument(document: TextDocument, changes: readonly TextDocumentContentChangeEvent[]) {
-		if (!isEnabled) {
+	function onDidChangeTextDocument({ document, contentChanges, reason }: TextDocumentChangeEvent) {
+		if (!isEnabled || contentChanges.length === 0 || reason === TextDocumentChangeReason.Undo) {
 			return;
 		}
-		let activeDocument = window.activeTextEditor && window.activeTextEditor.document;
-		if (document !== activeDocument || changes.length === 0) {
+		const activeDocument = window.activeTextEditor && window.activeTextEditor.document;
+		if (document !== activeDocument) {
 			return;
 		}
 		if (timeout) {
 			timeout.dispose();
 		}
-		let lastChange = changes[changes.length - 1];
-		let lastCharacter = lastChange.text[lastChange.text.length - 1];
+
+		const lastChange = contentChanges[contentChanges.length - 1];
+		const lastCharacter = lastChange.text[lastChange.text.length - 1];
 		if (lastChange.rangeLength > 0 || lastCharacter !== '>' && lastCharacter !== '/') {
 			return;
 		}
-		let rangeStart = lastChange.range.start;
-		let version = document.version;
+		const rangeStart = lastChange.range.start;
+		const version = document.version;
 		timeout = runtime.timer.setTimeout(() => {
-			let position = new Position(rangeStart.line, rangeStart.character + lastChange.text.length);
+			const position = new Position(rangeStart.line, rangeStart.character + lastChange.text.length);
 			tagProvider(document, position).then(text => {
 				if (text && isEnabled) {
-					let activeEditor = window.activeTextEditor;
+					const activeEditor = window.activeTextEditor;
 					if (activeEditor) {
-						let activeDocument = activeEditor.document;
+						const activeDocument = activeEditor.document;
 						if (document === activeDocument && activeDocument.version === version) {
-							let selections = activeEditor.selections;
+							const selections = activeEditor.selections;
 							if (selections.length && selections.some(s => s.active.isEqual(position))) {
 								activeEditor.insertSnippet(new SnippetString(text), selections.map(s => s.active));
 							} else {