diff --git a/.changeset/mighty-fans-retire.md b/.changeset/mighty-fans-retire.md
new file mode 100644
index 000000000..a71832f0f
--- /dev/null
+++ b/.changeset/mighty-fans-retire.md
@@ -0,0 +1,7 @@
+---
+'@lion/button': patch
+'@lion/overlays': patch
+'@lion/tooltip': patch
+---
+
+Types for overlays, tooltip, button
diff --git a/.changeset/silly-mayflies-talk.md b/.changeset/silly-mayflies-talk.md
new file mode 100644
index 000000000..6b10aaf96
--- /dev/null
+++ b/.changeset/silly-mayflies-talk.md
@@ -0,0 +1,9 @@
+---
+'@lion/core': minor
+---
+
+EventTargetShim
+
+#### Features
+
+EventTargetShim is a base class that shims EventTarget for full browser support.
diff --git a/.changeset/witty-paws-care.md b/.changeset/witty-paws-care.md
new file mode 100644
index 000000000..e00b1c7ed
--- /dev/null
+++ b/.changeset/witty-paws-care.md
@@ -0,0 +1,9 @@
+---
+'@lion/core': minor
+---
+
+EventTargetShim
+
+#### Features
+
+EventTargetShim is a base class that works like EventTarget, on all browsers.
diff --git a/packages/core/index.d.ts b/packages/core/index.d.ts
index 901842b0d..6c2f0acbe 100644
--- a/packages/core/index.d.ts
+++ b/packages/core/index.d.ts
@@ -17,6 +17,7 @@ export { DisabledWithTabIndexMixin } from './src/DisabledWithTabIndexMixin.js';
 export { SlotMixin } from './src/SlotMixin.js';
 export { UpdateStylesMixin } from './src/UpdateStylesMixin.js';
 export { browserDetection } from './src/browserDetection.js';
+export { EventTargetShim } from './src/EventTargetShim.js';
 export {
   css,
   CSSResult,
diff --git a/packages/core/index.js b/packages/core/index.js
index 3e3c95088..0825204b8 100644
--- a/packages/core/index.js
+++ b/packages/core/index.js
@@ -56,3 +56,4 @@ export { DisabledWithTabIndexMixin } from './src/DisabledWithTabIndexMixin.js';
 export { SlotMixin } from './src/SlotMixin.js';
 export { UpdateStylesMixin } from './src/UpdateStylesMixin.js';
 export { browserDetection } from './src/browserDetection.js';
+export { EventTargetShim } from './src/EventTargetShim.js';
diff --git a/packages/core/src/EventTargetShim.js b/packages/core/src/EventTargetShim.js
new file mode 100644
index 000000000..28afc834b
--- /dev/null
+++ b/packages/core/src/EventTargetShim.js
@@ -0,0 +1,33 @@
+export class EventTargetShim {
+  constructor() {
+    const delegate = document.createDocumentFragment();
+
+    /**
+     *
+     * @param {string} type
+     * @param {EventListener} listener
+     * @param {Object} [opts]
+     */
+    const delegatedAddEventListener = (type, listener, opts) =>
+      delegate.addEventListener(type, listener, opts);
+
+    /**
+     * @param {string} type
+     * @param {EventListener} listener
+     * @param {Object} [opts]
+     */
+    const delegatedRemoveEventListener = (type, listener, opts) =>
+      delegate.removeEventListener(type, listener, opts);
+
+    /**
+     * @param {Event|CustomEvent} event
+     */
+    const delegatedDispatchEvent = event => delegate.dispatchEvent(event);
+
+    this.addEventListener = delegatedAddEventListener;
+
+    this.removeEventListener = delegatedRemoveEventListener;
+
+    this.dispatchEvent = delegatedDispatchEvent;
+  }
+}
diff --git a/packages/core/test/EventTargetShim.js b/packages/core/test/EventTargetShim.js
new file mode 100644
index 000000000..7478912a1
--- /dev/null
+++ b/packages/core/test/EventTargetShim.js
@@ -0,0 +1,41 @@
+import { expect } from '@open-wc/testing';
+import sinon from 'sinon';
+import { EventTargetShim } from '../src/EventTargetShim.js';
+
+describe('EventTargetShim', () => {
+  class NonElementClass extends EventTargetShim {}
+
+  it('implements "addEventListener"', async () => {
+    const nonElementClass = new NonElementClass();
+    const cb = sinon.spy();
+
+    nonElementClass.addEventListener('my-event', cb);
+    expect(cb).to.not.have.been.called;
+    nonElementClass.dispatchEvent(new Event('my-event'));
+    expect(cb).to.have.been.called;
+  });
+
+  it('implements "removeEventListener"', async () => {
+    const nonElementClass = new NonElementClass();
+    const cb = sinon.spy();
+
+    nonElementClass.addEventListener('my-event', cb);
+    expect(cb).to.not.have.been.called;
+    nonElementClass.dispatchEvent(new Event('my-event'));
+    expect(cb).to.have.been.calledOnce;
+
+    nonElementClass.removeEventListener('my-event', cb);
+    nonElementClass.dispatchEvent(new Event('my-event'));
+    expect(cb).to.have.been.calledOnce;
+  });
+
+  it('implements "dispatchEvent"', async () => {
+    const nonElementClass = new NonElementClass();
+    const cb = sinon.spy();
+
+    nonElementClass.addEventListener('my-event', cb);
+    expect(cb).to.not.have.been.called;
+    nonElementClass.dispatchEvent(new Event('my-event'));
+    expect(cb).to.have.been.called;
+  });
+});