From fff4aec6cfbd48566594a05f4af57dd0578977a8 Mon Sep 17 00:00:00 2001
From: Liam DeBeasi <liamdebeasi@users.noreply.github.com>
Date: Wed, 22 Jul 2020 12:09:31 -0400
Subject: [PATCH] fix(overlays): trap focus inside overlay components except
 toast (#21716)

fixes #21647
---
 .../components/action-sheet/action-sheet.tsx  |   8 +-
 .../components/action-sheet/test/basic/e2e.ts |  34 +++++
 core/src/components/alert/alert.tsx           |   7 +-
 core/src/components/alert/test/basic/e2e.ts   |  34 +++++
 .../src/components/datetime/test/basic/e2e.ts |  37 +++++
 core/src/components/loading/loading.tsx       |   8 +-
 core/src/components/loading/test/basic/e2e.ts |  34 +++++
 core/src/components/modal/modal.tsx           |   8 +-
 core/src/components/modal/test/basic/e2e.ts   |  37 +++++
 core/src/components/picker/picker.tsx         |   8 +-
 core/src/components/popover/popover.tsx       |   8 +-
 core/src/components/popover/test/basic/e2e.ts |  35 +++++
 .../components/popover/test/basic/index.html  |   8 +-
 core/src/utils/overlays-interface.ts          |   1 +
 core/src/utils/overlays.ts                    | 140 +++++++++++++++---
 15 files changed, 377 insertions(+), 30 deletions(-)

diff --git a/core/src/components/action-sheet/action-sheet.tsx b/core/src/components/action-sheet/action-sheet.tsx
index 5c8630d833..00aaa73ea1 100644
--- a/core/src/components/action-sheet/action-sheet.tsx
+++ b/core/src/components/action-sheet/action-sheet.tsx
@@ -26,6 +26,7 @@ import { mdLeaveAnimation } from './animations/md.leave';
 export class ActionSheet implements ComponentInterface, OverlayInterface {
 
   presented = false;
+  lastFocus?: HTMLElement;
   animation?: any;
   private wrapperEl?: HTMLElement;
   private groupEl?: HTMLElement;
@@ -250,7 +251,10 @@ export class ActionSheet implements ComponentInterface, OverlayInterface {
         onIonBackdropTap={this.onBackdropTap}
       >
         <ion-backdrop tappable={this.backdropDismiss}/>
-        <div class="action-sheet-wrapper" role="dialog" ref={el => this.wrapperEl = el}>
+
+        <div tabindex="0"></div>
+
+        <div class="action-sheet-wrapper ion-overlay-wrapper" role="dialog" ref={el => this.wrapperEl = el}>
           <div class="action-sheet-container">
             <div class="action-sheet-group" ref={el => this.groupEl = el}>
               {this.header !== undefined &&
@@ -292,6 +296,8 @@ export class ActionSheet implements ComponentInterface, OverlayInterface {
             }
           </div>
         </div>
+
+        <div tabindex="0"></div>
       </Host>
     );
   }
diff --git a/core/src/components/action-sheet/test/basic/e2e.ts b/core/src/components/action-sheet/test/basic/e2e.ts
index d96982cd3f..a98661d765 100644
--- a/core/src/components/action-sheet/test/basic/e2e.ts
+++ b/core/src/components/action-sheet/test/basic/e2e.ts
@@ -1,6 +1,40 @@
 import { testActionSheet, testActionSheetAlert, testActionSheetBackdrop } from '../test.utils';
+import { newE2EPage } from '@stencil/core/testing';
 
 const DIRECTORY = 'basic';
+const getActiveElementText = async (page) => {
+  const activeElement = await page.evaluateHandle(() => document.activeElement);
+  return await page.evaluate(el => el && el.textContent, activeElement);
+}
+
+test('action-sheet: focus trap', async () => {
+  const page = await newE2EPage({ url: '/src/components/action-sheet/test/basic?ionic:_testing=true' });
+
+  await page.click('#basic');
+  await page.waitForSelector('#basic');
+
+  let actionSheet = await page.find('ion-action-sheet');
+
+  expect(actionSheet).not.toBe(null);
+  await actionSheet.waitForVisible();
+
+  await page.keyboard.press('Tab');
+
+  const activeElementText = await getActiveElementText(page);
+  expect(activeElementText).toEqual('Delete');
+
+  await page.keyboard.down('Shift');
+  await page.keyboard.press('Tab');
+  await page.keyboard.up('Shift');
+
+  const activeElementTextTwo = await getActiveElementText(page);
+  expect(activeElementTextTwo).toEqual('Cancel');
+
+  await page.keyboard.press('Tab');
+
+  const activeElementTextThree = await getActiveElementText(page);
+  expect(activeElementTextThree).toEqual('Delete');
+});
 
 test('action-sheet: basic', async () => {
   await testActionSheet(DIRECTORY, '#basic');
diff --git a/core/src/components/alert/alert.tsx b/core/src/components/alert/alert.tsx
index a2793528d4..91a0f8854a 100644
--- a/core/src/components/alert/alert.tsx
+++ b/core/src/components/alert/alert.tsx
@@ -34,6 +34,7 @@ export class Alert implements ComponentInterface, OverlayInterface {
   private gesture?: Gesture;
 
   presented = false;
+  lastFocus?: HTMLElement;
 
   @Element() el!: HTMLIonAlertElement;
 
@@ -514,7 +515,9 @@ export class Alert implements ComponentInterface, OverlayInterface {
 
         <ion-backdrop tappable={this.backdropDismiss}/>
 
-        <div class="alert-wrapper" ref={el => this.wrapperEl = el}>
+        <div tabindex="0"></div>
+
+        <div class="alert-wrapper ion-overlay-wrapper" ref={el => this.wrapperEl = el}>
 
           <div class="alert-head">
             {header && <h2 id={hdrId} class="alert-title">{header}</h2>}
@@ -527,6 +530,8 @@ export class Alert implements ComponentInterface, OverlayInterface {
           {this.renderAlertButtons()}
 
         </div>
+
+        <div tabindex="0"></div>
       </Host>
     );
   }
diff --git a/core/src/components/alert/test/basic/e2e.ts b/core/src/components/alert/test/basic/e2e.ts
index d910271de1..ad2511d2b2 100644
--- a/core/src/components/alert/test/basic/e2e.ts
+++ b/core/src/components/alert/test/basic/e2e.ts
@@ -1,6 +1,40 @@
 import { testAlert } from '../test.utils';
+import { newE2EPage } from '@stencil/core/testing';
 
 const DIRECTORY = 'basic';
+const getActiveElementText = async (page) => {
+  const activeElement = await page.evaluateHandle(() => document.activeElement);
+  return await page.evaluate(el => el && el.textContent, activeElement);
+}
+
+test('alert: focus trap', async () => {
+  const page = await newE2EPage({ url: '/src/components/alert/test/basic?ionic:_testing=true' });
+
+  await page.click('#multipleButtons');
+  await page.waitForSelector('#multipleButtons');
+
+  let alert = await page.find('ion-alert');
+
+  expect(alert).not.toBe(null);
+  await alert.waitForVisible();
+
+  await page.keyboard.press('Tab');
+
+  const activeElementText = await getActiveElementText(page);
+  expect(activeElementText).toEqual('Open Modal');
+
+  await page.keyboard.down('Shift');
+  await page.keyboard.press('Tab');
+  await page.keyboard.up('Shift');
+
+  const activeElementTextTwo = await getActiveElementText(page);
+  expect(activeElementTextTwo).toEqual('Cancel');
+
+  await page.keyboard.press('Tab');
+
+  const activeElementTextThree = await getActiveElementText(page);
+  expect(activeElementTextThree).toEqual('Open Modal');
+});
 
 test(`alert: basic`, async () => {
   await testAlert(DIRECTORY, '#basic');
diff --git a/core/src/components/datetime/test/basic/e2e.ts b/core/src/components/datetime/test/basic/e2e.ts
index 99279a9205..b9a902dd94 100644
--- a/core/src/components/datetime/test/basic/e2e.ts
+++ b/core/src/components/datetime/test/basic/e2e.ts
@@ -1,5 +1,42 @@
 import { newE2EPage } from '@stencil/core/testing';
 
+const getActiveElementText = async (page) => {
+  const activeElement = await page.evaluateHandle(() => document.activeElement);
+  return await page.evaluate(el => el && el.textContent, activeElement);
+}
+
+test('datetime/picker: focus trap', async () => {
+  const page = await newE2EPage({ url: '/src/components/datetime/test/basic?ionic:_testing=true' });
+
+  await page.click('#datetime-part');
+  await page.waitForSelector('#datetime-part');
+
+  let datetime = await page.find('ion-datetime');
+
+  expect(datetime).not.toBe(null);
+  await datetime.waitForVisible();
+
+  // TODO fix
+  await page.waitFor(100);
+
+  await page.keyboard.press('Tab');
+
+  const activeElementText = await getActiveElementText(page);
+  expect(activeElementText).toEqual('Cancel');
+
+  await page.keyboard.down('Shift');
+  await page.keyboard.press('Tab');
+  await page.keyboard.up('Shift');
+
+  const activeElementTextTwo = await getActiveElementText(page);
+  expect(activeElementTextTwo).toEqual('1920');
+
+  await page.keyboard.press('Tab');
+
+  const activeElementTextThree = await getActiveElementText(page);
+  expect(activeElementTextThree).toEqual('Cancel');
+});
+
 test('datetime: basic', async () => {
   const page = await newE2EPage({
     url: '/src/components/datetime/test/basic?ionic:_testing=true'
diff --git a/core/src/components/loading/loading.tsx b/core/src/components/loading/loading.tsx
index 1e32fcdb9f..7ac6f3c081 100644
--- a/core/src/components/loading/loading.tsx
+++ b/core/src/components/loading/loading.tsx
@@ -27,6 +27,7 @@ export class Loading implements ComponentInterface, OverlayInterface {
   private durationTimeout: any;
 
   presented = false;
+  lastFocus?: HTMLElement;
 
   @Element() el!: HTMLIonLoadingElement;
 
@@ -194,7 +195,10 @@ export class Loading implements ComponentInterface, OverlayInterface {
         }}
       >
         <ion-backdrop visible={this.showBackdrop} tappable={this.backdropDismiss} />
-        <div class="loading-wrapper" role="dialog">
+
+        <div tabindex="0"></div>
+
+        <div class="loading-wrapper ion-overlay-wrapper" role="dialog">
           {spinner && (
             <div class="loading-spinner">
               <ion-spinner name={spinner} aria-hidden="true" />
@@ -203,6 +207,8 @@ export class Loading implements ComponentInterface, OverlayInterface {
 
           {message && <div class="loading-content" innerHTML={sanitizeDOMString(message)}></div>}
         </div>
+
+        <div tabindex="0"></div>
       </Host>
     );
   }
diff --git a/core/src/components/loading/test/basic/e2e.ts b/core/src/components/loading/test/basic/e2e.ts
index 8ad75c7ffb..e94e75e2c1 100644
--- a/core/src/components/loading/test/basic/e2e.ts
+++ b/core/src/components/loading/test/basic/e2e.ts
@@ -1,6 +1,40 @@
 import { testLoading } from '../test.utils';
+import { newE2EPage } from '@stencil/core/testing';
 
 const DIRECTORY = 'basic';
+const getActiveElementText = async (page) => {
+  const activeElement = await page.evaluateHandle(() => document.activeElement);
+  return await page.evaluate(el => el && el.textContent, activeElement);
+}
+
+test('loading: focus trap', async () => {
+  const page = await newE2EPage({ url: '/src/components/loading/test/basic?ionic:_testing=true' });
+
+  await page.click('#html-content-loading');
+  await page.waitForSelector('#html-content-loading');
+
+  let loading = await page.find('ion-loading');
+
+  expect(loading).not.toBe(null);
+  await loading.waitForVisible();
+
+  await page.keyboard.press('Tab');
+
+  const activeElementText = await getActiveElementText(page);
+  expect(activeElementText).toEqual('Click impatiently to load faster');
+
+  await page.keyboard.down('Shift');
+  await page.keyboard.press('Tab');
+  await page.keyboard.up('Shift');
+
+  const activeElementTextTwo = await getActiveElementText(page);
+  expect(activeElementTextTwo).toEqual('Click impatiently to load faster');
+
+  await page.keyboard.press('Tab');
+
+  const activeElementTextThree = await getActiveElementText(page);
+  expect(activeElementTextThree).toEqual('Click impatiently to load faster');
+});
 
 test('loading: basic', async () => {
   await testLoading(DIRECTORY, '#basic-loading');
diff --git a/core/src/components/modal/modal.tsx b/core/src/components/modal/modal.tsx
index 714ea3f346..f09d06a83c 100644
--- a/core/src/components/modal/modal.tsx
+++ b/core/src/components/modal/modal.tsx
@@ -34,6 +34,7 @@ export class Modal implements ComponentInterface, OverlayInterface {
   // Whether or not modal is being dismissed via gesture
   private gestureAnimationDismissing = false;
   presented = false;
+  lastFocus?: HTMLElement;
   animation?: Animation;
 
   @Element() el!: HTMLIonModalElement;
@@ -289,11 +290,16 @@ export class Modal implements ComponentInterface, OverlayInterface {
         <ion-backdrop visible={this.showBackdrop} tappable={this.backdropDismiss}/>
 
         {mode === 'ios' && <div class="modal-shadow"></div>}
+
+        <div tabindex="0"></div>
+
         <div
           role="dialog"
-          class="modal-wrapper"
+          class="modal-wrapper ion-overlay-wrapper"
         >
         </div>
+
+        <div tabindex="0"></div>
       </Host>
     );
   }
diff --git a/core/src/components/modal/test/basic/e2e.ts b/core/src/components/modal/test/basic/e2e.ts
index 2a778dd415..ff10d74118 100644
--- a/core/src/components/modal/test/basic/e2e.ts
+++ b/core/src/components/modal/test/basic/e2e.ts
@@ -1,6 +1,43 @@
 import { testModal } from '../test.utils';
+import { newE2EPage } from '@stencil/core/testing';
 
 const DIRECTORY = 'basic';
+const getActiveElementText = async (page) => {
+  const activeElement = await page.evaluateHandle(() => document.activeElement);
+  return await page.evaluate(el => el && el.textContent, activeElement);
+}
+
+test('modal: focus trap', async () => {
+  const page = await newE2EPage({ url: '/src/components/modal/test/basic?ionic:_testing=true' });
+
+  await page.click('#basic-modal');
+  await page.waitForSelector('#basic-modal');
+
+  let modal = await page.find('ion-modal');
+
+  expect(modal).not.toBe(null);
+  await modal.waitForVisible();
+
+  // TODO fix
+  await page.waitFor(50);
+
+  await page.keyboard.press('Tab');
+
+  const activeElementText = await getActiveElementText(page);
+  expect(activeElementText).toEqual('Dismiss Modal');
+
+  await page.keyboard.down('Shift');
+  await page.keyboard.press('Tab');
+  await page.keyboard.up('Shift');
+
+  const activeElementTextTwo = await getActiveElementText(page);
+  expect(activeElementTextTwo).toEqual('Dismiss Modal');
+
+  await page.keyboard.press('Tab');
+
+  const activeElementTextThree = await getActiveElementText(page);
+  expect(activeElementTextThree).toEqual('Dismiss Modal');
+});
 
 test('modal: basic', async () => {
   await testModal(DIRECTORY, '#basic-modal');
diff --git a/core/src/components/picker/picker.tsx b/core/src/components/picker/picker.tsx
index 83041163b0..595a8ae136 100644
--- a/core/src/components/picker/picker.tsx
+++ b/core/src/components/picker/picker.tsx
@@ -21,6 +21,7 @@ import { iosLeaveAnimation } from './animations/ios.leave';
 })
 export class Picker implements ComponentInterface, OverlayInterface {
   private durationTimeout: any;
+  lastFocus?: HTMLElement;
 
   @Element() el!: HTMLIonPickerElement;
 
@@ -236,7 +237,10 @@ export class Picker implements ComponentInterface, OverlayInterface {
           tappable={this.backdropDismiss}
         >
         </ion-backdrop>
-        <div class="picker-wrapper" role="dialog">
+
+        <div tabindex="0"></div>
+
+        <div class="picker-wrapper ion-overlay-wrapper" role="dialog">
           <div class="picker-toolbar">
             {this.buttons.map(b => (
               <div class={buttonWrapperClass(b)}>
@@ -259,6 +263,8 @@ export class Picker implements ComponentInterface, OverlayInterface {
             <div class="picker-below-highlight"></div>
           </div>
         </div>
+
+        <div tabindex="0"></div>
       </Host>
     );
   }
diff --git a/core/src/components/popover/popover.tsx b/core/src/components/popover/popover.tsx
index f7fbd61887..3584883e1a 100644
--- a/core/src/components/popover/popover.tsx
+++ b/core/src/components/popover/popover.tsx
@@ -28,6 +28,7 @@ export class Popover implements ComponentInterface, OverlayInterface {
   private usersElement?: HTMLElement;
 
   presented = false;
+  lastFocus?: HTMLElement;
 
   @Element() el!: HTMLIonPopoverElement;
 
@@ -219,10 +220,15 @@ export class Popover implements ComponentInterface, OverlayInterface {
         onIonBackdropTap={this.onBackdropTap}
       >
         <ion-backdrop tappable={this.backdropDismiss} visible={this.showBackdrop}/>
-        <div class="popover-wrapper">
+
+        <div tabindex="0"></div>
+
+        <div class="popover-wrapper ion-overlay-wrapper">
           <div class="popover-arrow"></div>
           <div class="popover-content"></div>
         </div>
+
+        <div tabindex="0"></div>
       </Host>
     );
   }
diff --git a/core/src/components/popover/test/basic/e2e.ts b/core/src/components/popover/test/basic/e2e.ts
index 9333fc134f..f586ea2010 100644
--- a/core/src/components/popover/test/basic/e2e.ts
+++ b/core/src/components/popover/test/basic/e2e.ts
@@ -1,7 +1,42 @@
 import { testPopover } from '../test.utils';
+import { newE2EPage } from '@stencil/core/testing';
 
 const DIRECTORY = 'basic';
 
+const getActiveElementText = async (page) => {
+  const activeElement = await page.evaluateHandle(() => document.activeElement);
+  return await page.evaluate(el => el && el.textContent, activeElement);
+}
+
+test('popover: focus trap', async () => {
+  const page = await newE2EPage({ url: '/src/components/popover/test/basic?ionic:_testing=true' });
+
+  await page.click('#basic-popover');
+  await page.waitForSelector('#basic-popover');
+
+  let popover = await page.find('ion-popover');
+
+  expect(popover).not.toBe(null);
+  await popover.waitForVisible();
+
+  await page.keyboard.press('Tab');
+
+  const activeElementText = await getActiveElementText(page);
+  expect(activeElementText).toEqual('Item 0');
+
+  await page.keyboard.down('Shift');
+  await page.keyboard.press('Tab');
+  await page.keyboard.up('Shift');
+
+  const activeElementTextTwo = await getActiveElementText(page);
+  expect(activeElementTextTwo).toEqual('Item 3');
+
+  await page.keyboard.press('Tab');
+
+  const activeElementTextThree = await getActiveElementText(page);
+  expect(activeElementTextThree).toEqual('Item 0');
+});
+
 test('popover: basic', async () => {
   await testPopover(DIRECTORY, '#basic-popover');
 });
diff --git a/core/src/components/popover/test/basic/index.html b/core/src/components/popover/test/basic/index.html
index 354b34d79b..d404235fb2 100644
--- a/core/src/components/popover/test/basic/index.html
+++ b/core/src/components/popover/test/basic/index.html
@@ -75,10 +75,10 @@
           <ion-content>
             <ion-list>
               <ion-list-header><ion-label>Ionic</ion-label></ion-list-header>
-              <ion-item><ion-label>Item 0</ion-label></ion-item>
-              <ion-item><ion-label>Item 1</ion-label></ion-item>
-              <ion-item><ion-label>Item 2</ion-label></ion-item>
-              <ion-item><ion-label>Item 3</ion-label></ion-item>
+              <ion-item button><ion-label>Item 0</ion-label></ion-item>
+              <ion-item button><ion-label>Item 1</ion-label></ion-item>
+              <ion-item button><ion-label>Item 2</ion-label></ion-item>
+              <ion-item button><ion-label>Item 3</ion-label></ion-item>
             </ion-list>
           </ion-content>
         `;
diff --git a/core/src/utils/overlays-interface.ts b/core/src/utils/overlays-interface.ts
index 273b4cec8a..ace690ca52 100644
--- a/core/src/utils/overlays-interface.ts
+++ b/core/src/utils/overlays-interface.ts
@@ -35,6 +35,7 @@ export interface OverlayController {
 export interface HTMLIonOverlayElement extends HTMLStencilElement {
   overlayIndex: number;
   backdropDismiss?: boolean;
+  lastFocus?: HTMLElement;
 
   dismiss(data?: any, role?: string): Promise<boolean>;
 }
diff --git a/core/src/utils/overlays.ts b/core/src/utils/overlays.ts
index cff746ec8d..2e191bc108 100644
--- a/core/src/utils/overlays.ts
+++ b/core/src/utils/overlays.ts
@@ -3,6 +3,7 @@ import { getIonMode } from '../global/ionic-global';
 import { ActionSheetOptions, AlertOptions, Animation, AnimationBuilder, BackButtonEvent, HTMLIonOverlayElement, IonicConfig, LoadingOptions, ModalOptions, OverlayInterface, PickerOptions, PopoverOptions, ToastOptions } from '../interface';
 
 import { OVERLAY_BACK_BUTTON_PRIORITY } from './hardware-back-button';
+import { getElementRoot } from './helpers';
 
 let lastId = 0;
 
@@ -62,19 +63,128 @@ export const createOverlay = <T extends HTMLIonOverlayElement>(tagName: string,
   return Promise.resolve() as any;
 };
 
+const focusableQueryString = '[tabindex]:not([tabindex^="-"]), input, textarea, button, select, .ion-focusable';
+
+const focusFirstDescendant = (ref: Element, overlay: HTMLIonOverlayElement) => {
+  let firstInput = ref.querySelector(focusableQueryString) as HTMLElement | null;
+
+  const shadowRoot = firstInput && firstInput.shadowRoot;
+  if (shadowRoot) {
+    firstInput = shadowRoot.querySelector('input, textarea, button, select');
+  }
+
+  if (firstInput) {
+    firstInput.focus();
+  } else {
+    // Focus overlay instead of letting focus escape
+    overlay.focus();
+  }
+};
+
+const focusLastDescendant = (ref: Element, overlay: HTMLIonOverlayElement) => {
+  const inputs = Array.from(ref.querySelectorAll(focusableQueryString)) as HTMLElement[];
+  let lastInput = inputs.length > 0 ? inputs[inputs.length - 1] : null;
+
+  const shadowRoot = lastInput && lastInput.shadowRoot;
+  if (shadowRoot) {
+    lastInput = shadowRoot.querySelector('input, textarea, button, select');
+  }
+
+  if (lastInput) {
+    lastInput.focus();
+  } else {
+    // Focus overlay instead of letting focus escape
+    overlay.focus();
+  }
+};
+
+/**
+ * Traps keyboard focus inside of overlay components.
+ * Based on https://w3c.github.io/aria-practices/examples/dialog-modal/alertdialog.html
+ * This includes the following components: Action Sheet, Alert, Loading, Modal,
+ * Picker, and Popover.
+ * Should NOT include: Toast
+ */
+const trapKeyboardFocus = (ev: Event, doc: Document) => {
+  const lastOverlay = getOverlay(doc);
+  const target = ev.target as HTMLElement | null;
+
+  // If no active overlay, ignore this event
+  if (!lastOverlay || !target) { return; }
+
+  /**
+   * If we are focusing the overlay, clear
+   * the last focused element so that hitting
+   * tab activates the first focusable element
+   * in the overlay wrapper.
+   */
+  if (lastOverlay === target) {
+    lastOverlay.lastFocus = undefined;
+
+    /**
+     * Otherwise, we must be focusing an element
+     * inside of the overlay. The two possible options
+     * here are an input/button/etc or the ion-focus-trap
+     * element. The focus trap element is used to prevent
+     * the keyboard focus from leaving the overlay when
+     * using Tab or screen assistants.
+     */
+  } else {
+    /**
+     * We do not want to focus the traps, so get the overlay
+     * wrapper element as the traps live outside of the wrapper.
+     */
+    const overlayRoot = getElementRoot(lastOverlay);
+    const overlayWrapper = overlayRoot.querySelector('.ion-overlay-wrapper');
+
+    if (!overlayWrapper) { return; }
+
+    /**
+     * If the target is inside the wrapper, let the browser
+     * focus as normal and keep a log of the last focused element.
+     */
+    if (overlayWrapper.contains(target)) {
+      lastOverlay.lastFocus = target;
+    } else {
+      /**
+       * Otherwise, we must have focused one of the focus traps.
+       * We need to wrap the focus to either the first element
+       * or the last element.
+       */
+
+      /**
+       * Once we call `focusFirstDescendant` and focus the first
+       * descendant, another focus event will fire which will
+       * cause `lastOverlay.lastFocus` to be updated before
+       * we can run the code after that. We will cache the value
+       * here to avoid that.
+       */
+      const lastFocus = lastOverlay.lastFocus;
+
+      // Focus the first element in the overlay wrapper
+      focusFirstDescendant(overlayWrapper, lastOverlay);
+
+      /**
+       * If the cached last focused element is the
+       * same as the active element, then we need
+       * to wrap focus to the last descendant. This happens
+       * when the first descendant is focused, and the user
+       * presses Shift + Tab. The previous line will focus
+       * the same descendant again (the first one), causing
+       * last focus to equal the active element.
+       */
+      if (lastFocus === doc.activeElement) {
+        focusLastDescendant(overlayWrapper, lastOverlay);
+      }
+      lastOverlay.lastFocus = doc.activeElement as HTMLElement;
+    }
+  }
+};
+
 export const connectListeners = (doc: Document) => {
   if (lastId === 0) {
     lastId = 1;
-    // trap focus inside overlays
-    doc.addEventListener('focusin', ev => {
-      const lastOverlay = getOverlay(doc);
-      if (lastOverlay && lastOverlay.backdropDismiss && !isDescendant(lastOverlay, ev.target as HTMLElement)) {
-        const firstInput = lastOverlay.querySelector('input,button') as HTMLElement | null;
-        if (firstInput) {
-          firstInput.focus();
-        }
-      }
-    });
+    doc.addEventListener('focus', ev => trapKeyboardFocus(ev, doc), true);
 
     // handle back-button click
     doc.addEventListener('ionBackButton', ev => {
@@ -247,16 +357,6 @@ export const isCancel = (role: string | undefined): boolean => {
   return role === 'cancel' || role === BACKDROP;
 };
 
-const isDescendant = (parent: HTMLElement, child: HTMLElement | null) => {
-  while (child) {
-    if (child === parent) {
-      return true;
-    }
-    child = child.parentElement;
-  }
-  return false;
-};
-
 const defaultGate = (h: any) => h();
 
 export const safeCall = (handler: any, arg?: any) => {