diff --git a/types/chrome-apps/index.d.ts b/types/chrome-apps/index.d.ts
index 8873e80da2..c947a8d12c 100644
--- a/types/chrome-apps/index.d.ts
+++ b/types/chrome-apps/index.d.ts
@@ -13274,7 +13274,7 @@ interface HTMLElement {
     /**
      * ❗ Unprefixed version are not available as of Chrome 68, in Chrome apps ❗
      */
-    requestFullscreen(): void;
+    requestFullscreen(): Promise<void>;
     /**
      * ❗ Unprefixed version are not available as of Chrome 68, in Chrome apps ❗
      */
diff --git a/types/chrome-apps/test/index.ts b/types/chrome-apps/test/index.ts
index 499a34bab1..61251e296a 100644
--- a/types/chrome-apps/test/index.ts
+++ b/types/chrome-apps/test/index.ts
@@ -2012,5 +2012,8 @@ appview.connect('id of app');
 document.appendChild(appview);
 //#endregion
 
+// #region HTMLElement correctly subtypes Element in TS3.1.
+const htmlElement = document.querySelector('zzzzzz') as HTMLElement;
+//#endregion