diff --git a/package.json b/package.json
index 435ee48571..fb180ddd41 100644
--- a/package.json
+++ b/package.json
@@ -9,7 +9,7 @@
   "main": "index.js",
   "playwright": {
     "chromium_revision": "724623",
-    "firefox_revision": "1012",
+    "firefox_revision": "1013",
     "webkit_revision": "1092"
   },
   "scripts": {
diff --git a/src/chromium/crPage.ts b/src/chromium/crPage.ts
index 776809c9cd..a624e0309e 100644
--- a/src/chromium/crPage.ts
+++ b/src/chromium/crPage.ts
@@ -38,7 +38,6 @@ import { CRBrowser } from './crBrowser';
 import { BrowserContext } from '../browserContext';
 import * as types from '../types';
 import { ConsoleMessage } from '../console';
-import * as accessibility from '../accessibility';
 import * as platform from '../platform';
 
 const UTILITY_WORLD_NAME = '__playwright_utility_world__';
diff --git a/src/firefox/ffPage.ts b/src/firefox/ffPage.ts
index 6b834d933f..ca1528d830 100644
--- a/src/firefox/ffPage.ts
+++ b/src/firefox/ffPage.ts
@@ -16,7 +16,7 @@
  */
 
 import * as frames from '../frames';
-import { assert, helper, RegisteredListener, debugError } from '../helper';
+import { helper, RegisteredListener, debugError } from '../helper';
 import * as dom from '../dom';
 import { FFSession } from './ffConnection';
 import { FFExecutionContext } from './ffExecutionContext';
@@ -30,10 +30,11 @@ import { BrowserContext } from '../browserContext';
 import { getAccessibilityTree } from './ffAccessibility';
 import * as network from '../network';
 import * as types from '../types';
-import * as accessibility from '../accessibility';
 import * as platform from '../platform';
 import { kScreenshotDuringNavigationError } from '../screenshotter';
 
+const UTILITY_WORLD_NAME = '__playwright_utility_world__';
+
 export class FFPage implements PageDelegate {
   readonly rawMouse: RawMouseImpl;
   readonly rawKeyboard: RawKeyboardImpl;
@@ -70,7 +71,7 @@ export class FFPage implements PageDelegate {
 
   async _initialize() {
     const promises: Promise<any>[] = [
-      this._session.send('Runtime.enable'),
+      this._session.send('Runtime.enable').then(() => this._ensureIsolatedWorld(UTILITY_WORLD_NAME)),
       this._session.send('Network.enable'),
       this._session.send('Page.enable'),
       this._session.send('Page.setInterceptFileChooserDialog', { enabled: true })
@@ -87,6 +88,13 @@ export class FFPage implements PageDelegate {
     await Promise.all(promises);
   }
 
+  async _ensureIsolatedWorld(name: string) {
+    await this._session.send('Page.addScriptToEvaluateOnNewDocument', {
+      script: '',
+      worldName: name,
+    });
+  }
+
   _onExecutionContextCreated(payload: Protocol.Runtime.executionContextCreatedPayload) {
     const {executionContextId, auxData} = payload;
     const frame = this._page._frameManager.frame(auxData ? auxData.frameId : null);
@@ -94,8 +102,10 @@ export class FFPage implements PageDelegate {
       return;
     const delegate = new FFExecutionContext(this._session, executionContextId);
     const context = new dom.FrameExecutionContext(delegate, frame);
-    frame._contextCreated('main', context);
-    frame._contextCreated('utility', context);
+    if (auxData.name === UTILITY_WORLD_NAME)
+      frame._contextCreated('utility', context);
+    else if (!auxData.name)
+      frame._contextCreated('main', context);
     this._contextIdToContext.set(executionContextId, context);
   }
 
@@ -351,8 +361,12 @@ export class FFPage implements PageDelegate {
   }
 
   async adoptElementHandle<T extends Node>(handle: dom.ElementHandle<T>, to: dom.FrameExecutionContext): Promise<dom.ElementHandle<T>> {
-    assert(false, 'Multiple isolated worlds are not implemented');
-    return handle;
+    const result = await this._session.send('Page.adoptNode', {
+      frameId: handle._context.frame._id,
+      objectId: toRemoteObject(handle).objectId!,
+      executionContextId: (to._delegate as FFExecutionContext)._executionContextId
+    });
+    return to._createHandle(result.remoteObject) as dom.ElementHandle<T>;
   }
 
   async getAccessibilityTree(needle?: dom.ElementHandle) {
diff --git a/test/click.spec.js b/test/click.spec.js
index 4ae9189abf..d0bd619e83 100644
--- a/test/click.spec.js
+++ b/test/click.spec.js
@@ -37,7 +37,7 @@ module.exports.describe = function({testRunner, expect, playwright, FFOX, CHROMI
       await page.click('circle');
       expect(await page.evaluate(() => window.__CLICKED)).toBe(42);
     });
-    it.skip(FFOX)('should click the button if window.Node is removed', async({page, server}) => {
+    it('should click the button if window.Node is removed', async({page, server}) => {
       await page.goto(server.PREFIX + '/input/button.html');
       await page.evaluate(() => delete window.Node);
       await page.click('button');
diff --git a/test/elementhandle.spec.js b/test/elementhandle.spec.js
index 6374313025..0e66417bac 100644
--- a/test/elementhandle.spec.js
+++ b/test/elementhandle.spec.js
@@ -182,7 +182,7 @@ module.exports.describe = function({testRunner, expect, FFOX, CHROMIUM, WEBKIT})
       await button.click();
       expect(await page.evaluate(() => result)).toBe('Clicked');
     });
-    it.skip(FFOX)('should work with Node removed', async({page, server}) => {
+    it('should work with Node removed', async({page, server}) => {
       await page.goto(server.PREFIX + '/input/button.html');
       await page.evaluate(() => delete window['Node']);
       const button = await page.$('button');
@@ -239,7 +239,7 @@ module.exports.describe = function({testRunner, expect, FFOX, CHROMIUM, WEBKIT})
       await button.hover();
       expect(await page.evaluate(() => document.querySelector('button:hover').id)).toBe('button-6');
     });
-    it.skip(FFOX)('should work when Node is removed', async({page, server}) => {
+    it('should work when Node is removed', async({page, server}) => {
       await page.goto(server.PREFIX + '/input/scrollable.html');
       await page.evaluate(() => delete window['Node']);
       const button = await page.$('#button-6');
@@ -257,7 +257,7 @@ module.exports.describe = function({testRunner, expect, FFOX, CHROMIUM, WEBKIT})
         expect(Math.round(ratio * 10)).toBe(10 - i);
       }
     });
-    it.skip(FFOX)('should work when Node is removed', async({page, server}) => {
+    it('should work when Node is removed', async({page, server}) => {
       await page.goto(server.PREFIX + '/offscreenbuttons.html');
       await page.evaluate(() => delete window['Node']);
       for (let i = 0; i < 11; ++i) {
@@ -290,7 +290,7 @@ module.exports.describe = function({testRunner, expect, FFOX, CHROMIUM, WEBKIT})
       await handle.fill('some value');
       expect(await page.evaluate(() => result)).toBe('some value');
     });
-    it.skip(FFOX)('should fill input when Node is removed', async({page, server}) => {
+    it('should fill input when Node is removed', async({page, server}) => {
       await page.goto(server.PREFIX + '/input/textarea.html');
       await page.evaluate(() => delete window['Node']);
       const handle = await page.$('input');
diff --git a/test/mouse.spec.js b/test/mouse.spec.js
index 4586338086..adc0542613 100644
--- a/test/mouse.spec.js
+++ b/test/mouse.spec.js
@@ -98,7 +98,7 @@ module.exports.describe = function({testRunner, expect, FFOX, CHROMIUM, WEBKIT,
       await page.hover('#button-91');
       expect(await page.evaluate(() => document.querySelector('button:hover').id)).toBe('button-91');
     });
-    it.skip(FFOX)('should trigger hover state with removed window.Node', async({page, server}) => {
+    it('should trigger hover state with removed window.Node', async({page, server}) => {
       await page.goto(server.PREFIX + '/input/scrollable.html');
       await page.evaluate(() => delete window.Node);
       await page.hover('#button-6');
diff --git a/test/page.spec.js b/test/page.spec.js
index 5baedc88c4..ea2ae6a10d 100644
--- a/test/page.spec.js
+++ b/test/page.spec.js
@@ -960,7 +960,7 @@ module.exports.describe = function({testRunner, expect, headless, playwright, FF
       expect(error.message).toContain('Indices must be numbers');
     });
     // @see https://github.com/GoogleChrome/puppeteer/issues/3327
-    it.skip(FFOX)('should work when re-defining top-level Event class', async({page, server}) => {
+    it('should work when re-defining top-level Event class', async({page, server}) => {
       await page.goto(server.PREFIX + '/input/select.html');
       await page.evaluate(() => window.Event = null);
       await page.select('select', 'blue');
diff --git a/test/waittask.spec.js b/test/waittask.spec.js
index 536581ebc6..384907e878 100644
--- a/test/waittask.spec.js
+++ b/test/waittask.spec.js
@@ -246,7 +246,7 @@ module.exports.describe = function({testRunner, expect, product, playwright, FFO
       await frame.waitForSelector('div');
     });
 
-    it.skip(FFOX)('should work with removed MutationObserver', async({page, server}) => {
+    it('should work with removed MutationObserver', async({page, server}) => {
       await page.evaluate(() => delete window.MutationObserver);
       const [handle] = await Promise.all([
         page.waitForSelector('.zombo'),
@@ -318,7 +318,7 @@ module.exports.describe = function({testRunner, expect, product, playwright, FFO
       await waitForSelector;
       expect(boxFound).toBe(true);
     });
-    it.skip(FFOX)('should wait for visible', async({page, server}) => {
+    it('should wait for visible', async({page, server}) => {
       let divFound = false;
       const waitForSelector = page.waitForSelector('div').then(() => divFound = true);
       await page.setContent(`<div style='display: none; visibility: hidden;'>1</div>`);