diff --git a/examples/example-dockpanel-iife/index.html b/examples/example-dockpanel-iife/index.html
index 70a56367b..629196ad6 100644
--- a/examples/example-dockpanel-iife/index.html
+++ b/examples/example-dockpanel-iife/index.html
@@ -14,6 +14,7 @@
   <script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.auto.js"></script>
 
   <script src="../../packages/algorithm/dist/index.js"></script>
+  <script src="../../packages/coreutils/dist/index.js"></script>
   <script src="../../packages/collections/dist/index.js"></script>
   <script src="../../packages/properties/dist/index.js"></script>
   <script src="../../packages/messaging/dist/index.js"></script>
diff --git a/packages/coreutils/src/schedule.ts b/packages/coreutils/src/schedule.ts
index 8385b0498..f8bc32f8a 100644
--- a/packages/coreutils/src/schedule.ts
+++ b/packages/coreutils/src/schedule.ts
@@ -1,21 +1,21 @@
 // Copyright (c) Jupyter Development Team.
 // Distributed under the terms of the Modified BSD License.
 
+/**
+ * Test whether the client is a brower and can request animation frames.
+ */
+const BROWSER =
+  typeof document !== 'undefined' &&
+  typeof requestAnimationFrame === 'function';
+
 /**
  * A composite type for callback handles, useful for unscheduling the callback.
  */
-type Handle =
+export type ScheduleHandle =
   | ReturnType<typeof requestAnimationFrame>
   | ReturnType<typeof setImmediate>
   | ReturnType<typeof setTimeout>;
 
-/**
- * Whether the client is a brower and can request animation frames.
- */
-const BROWSER =
-  typeof document !== 'undefined' &&
-  typeof requestAnimationFrame === 'function';
-
 /**
  * Schedules a function for invocation as soon as possible asynchronously.
  *
@@ -23,7 +23,7 @@ const BROWSER =
  *
  * @returns A handle that can be used to `unschedule` the `fn` if possible.
  */
-export function schedule(fn: () => unknown): Handle {
+export function schedule(fn: () => unknown): ScheduleHandle {
   if (BROWSER && document.visibilityState === 'hidden') {
     return setTimeout(fn);
   }
@@ -38,7 +38,7 @@ export function schedule(fn: () => unknown): Handle {
  *
  * @param handle The handle for the callback to unschedule.
  */
-export function unschedule(handle: Handle): void {
+export function unschedule(handle: ScheduleHandle): void {
   if (BROWSER && document.visibilityState === 'hidden') {
     return clearTimeout(handle as ReturnType<typeof setTimeout>);
   }
diff --git a/review/api/coreutils.api.md b/review/api/coreutils.api.md
index a3204772d..6d4414323 100644
--- a/review/api/coreutils.api.md
+++ b/review/api/coreutils.api.md
@@ -4,6 +4,8 @@
 
 ```ts
 
+/// <reference types="node" />
+
 // @public
 export interface JSONArray extends Array<JSONValue> {
 }
@@ -106,12 +108,20 @@ export interface ReadonlyPartialJSONObject {
 // @public
 export type ReadonlyPartialJSONValue = JSONPrimitive | ReadonlyPartialJSONObject | ReadonlyPartialJSONArray;
 
+// Warning: (ae-forgotten-export) The symbol "Handle" needs to be exported by the entry point index.d.ts
+//
+// @public
+export function schedule(fn: () => unknown): Handle;
+
 // @public
 export class Token<T> {
     constructor(name: string);
     readonly name: string;
 }
 
+// @public
+export function unschedule(handle: Handle): void;
+
 // @public
 export namespace UUID {
     const uuid4: () => string;
diff --git a/review/api/polling.api.md b/review/api/polling.api.md
index 13bfd6c6d..645dc7439 100644
--- a/review/api/polling.api.md
+++ b/review/api/polling.api.md
@@ -56,14 +56,14 @@ export class Poll<T = any, U = any, V extends string = 'standby'> implements IOb
     get disposed(): ISignal<this, void>;
     get frequency(): IPoll.Frequency;
     set frequency(frequency: IPoll.Frequency);
+    get hidden(): boolean;
     get isDisposed(): boolean;
     readonly name: string;
     refresh(): Promise<void>;
     schedule(next?: Partial<IPoll.State<T, U, V> & {
         cancel: (last: IPoll.State<T, U, V>) => boolean;
     }>): Promise<void>;
-    get standby(): Poll.Standby | (() => boolean | Poll.Standby);
-    set standby(standby: Poll.Standby | (() => boolean | Poll.Standby));
+    standby: Poll.Standby | (() => boolean | Poll.Standby);
     start(): Promise<void>;
     get state(): IPoll.State<T, U, V>;
     stop(): Promise<void>;
@@ -78,6 +78,7 @@ export namespace Poll {
         auto?: boolean;
         factory: Factory<T, U, V>;
         frequency?: Partial<IPoll.Frequency>;
+        linger?: number;
         name?: string;
         standby?: Standby | (() => boolean | Standby);
     }