diff --git a/core/modules/ckeditor/tests/src/FunctionalJavascript/CKEditorIntegrationTest.php b/core/modules/ckeditor/tests/src/FunctionalJavascript/CKEditorIntegrationTest.php
index 14a3e71677..a9ee69719b 100644
--- a/core/modules/ckeditor/tests/src/FunctionalJavascript/CKEditorIntegrationTest.php
+++ b/core/modules/ckeditor/tests/src/FunctionalJavascript/CKEditorIntegrationTest.php
@@ -92,8 +92,8 @@ public function testFragmentLink() {
     $session->getPage();
 
     // Add a bottom margin to the title field to be sure the body field is not
-    // visible. PhantomJS runs with a resolution of 1024x768px.
-    $session->executeScript("document.getElementById('edit-title-0-value').style.marginBottom = '1200px';");
+    // visible.
+    $session->executeScript("document.getElementById('edit-title-0-value').style.marginBottom = window.innerHeight*2 +'px';");
 
     $this->assertSession()->waitForElementVisible('css', $ckeditor_id);
     // Check that the CKEditor-enabled body field is currently not visible in
diff --git a/core/modules/config_translation/tests/src/FunctionalJavascript/ConfigTranslationUiTest.php b/core/modules/config_translation/tests/src/FunctionalJavascript/ConfigTranslationUiTest.php
index 1c91fbcaa2..585d2d1d38 100644
--- a/core/modules/config_translation/tests/src/FunctionalJavascript/ConfigTranslationUiTest.php
+++ b/core/modules/config_translation/tests/src/FunctionalJavascript/ConfigTranslationUiTest.php
@@ -33,7 +33,7 @@ public function testViewContextualLink() {
     $this->drupalLogin($user);
 
     $this->drupalGet('node');
-    $contextualLinks = $this->assertSession()->waitForElement('css', '.contextual-links', 100000);
+    $contextualLinks = $this->assertSession()->waitForElement('css', '.contextual-links');
     $link = $contextualLinks->findLink('Translate view');
     $this->assertNotNull($link, 'Translate view contextual link added.');
   }
diff --git a/core/modules/settings_tray/tests/src/FunctionalJavascript/ConfigAccessTest.php b/core/modules/settings_tray/tests/src/FunctionalJavascript/ConfigAccessTest.php
index bc0f23d038..6b15be9425 100644
--- a/core/modules/settings_tray/tests/src/FunctionalJavascript/ConfigAccessTest.php
+++ b/core/modules/settings_tray/tests/src/FunctionalJavascript/ConfigAccessTest.php
@@ -51,7 +51,7 @@ public function testBlockConfigAccess() {
     // permission.
     $web_assert->fieldNotExists('settings[site_information][site_name]');
     $page->pressButton('Save Site branding');
-    $web_assert->assertWaitOnAjaxRequest();
+    $this->waitForOffCanvasToClose();
     $this->assertElementVisibleAfterWait('css', 'div:contains(The block configuration has been saved)');
     $web_assert->assertWaitOnAjaxRequest();
     // Confirm we did not save changes to the configuration.
diff --git a/core/modules/settings_tray/tests/src/FunctionalJavascript/OverriddenConfigurationTest.php b/core/modules/settings_tray/tests/src/FunctionalJavascript/OverriddenConfigurationTest.php
index a766524abb..cc37d6189c 100644
--- a/core/modules/settings_tray/tests/src/FunctionalJavascript/OverriddenConfigurationTest.php
+++ b/core/modules/settings_tray/tests/src/FunctionalJavascript/OverriddenConfigurationTest.php
@@ -58,7 +58,7 @@ public function testOverriddenConfigurationRemoved() {
     $this->openBlockForm($this->getBlockSelector($branding_block));
     $web_assert->fieldNotExists('settings[site_information][site_name]');
     $page->pressButton('Save Site branding');
-    $web_assert->assertWaitOnAjaxRequest();
+    $this->waitForOffCanvasToClose();
     $this->assertElementVisibleAfterWait('css', 'div:contains(The block configuration has been saved)');
     $web_assert->assertWaitOnAjaxRequest();
     // Confirm we did not save changes to the configuration.
@@ -91,7 +91,7 @@ public function testOverriddenConfigurationRemoved() {
     $this->openBlockForm($this->getBlockSelector($menu_block));
     $web_assert->elementNotExists('css', '#menu-overview');
     $page->pressButton('Save Main navigation');
-    $web_assert->assertWaitOnAjaxRequest();
+    $this->waitForOffCanvasToClose();
     $this->assertElementVisibleAfterWait('css', 'div:contains(The block configuration has been saved)');
     $web_assert->assertWaitOnAjaxRequest();
     // Confirm we did not save changes to the configuration.
diff --git a/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php b/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php
index b852a63fef..0e6b9d6251 100644
--- a/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php
+++ b/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php
@@ -67,8 +67,7 @@ protected function doTestBlocks($theme, $block_plugin, $new_page_text, $element_
     $block_id = $block->id();
     $this->drupalGet('user');
 
-    $web_assert->waitForElement('css', "$block_selector .contextual-links li a");
-    $link = $page->find('css', "$block_selector .contextual-links li a");
+    $link = $web_assert->waitForElement('css', "$block_selector .contextual-links li a");
     $this->assertEquals('Quick edit', $link->getHtml(), "'Quick edit' is the first contextual link for the block.");
     $this->assertContains("/admin/structure/block/manage/$block_id/settings-tray?destination=user/2", $link->getAttribute('href'));
 
@@ -140,7 +139,7 @@ protected function doTestBlocks($theme, $block_plugin, $new_page_text, $element_
     $this->waitForOffCanvasToClose();
     $this->getSession()->wait(100);
     $this->getSession()->executeScript("jQuery('[data-quickedit-entity-id]').trigger('mouseleave')");
-    $this->getSession()->getDriver()->mouseOver($this->getSession()->getPage()->find('css', static::TOOLBAR_EDIT_LINK_SELECTOR)->getXpath());
+    $this->getSession()->getPage()->find('css', static::TOOLBAR_EDIT_LINK_SELECTOR)->mouseOver();
     $this->assertEditModeDisabled();
     $this->assertNotEmpty($web_assert->waitForElement('css', '#drupal-live-announce:contains(Exited edit mode)'));
     $this->waitForNoElement('.contextual-toolbar-tab button:contains(Editing)');
diff --git a/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php b/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php
index 659a194e2e..fd163985e7 100644
--- a/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php
+++ b/core/modules/toolbar/tests/src/FunctionalJavascript/ToolbarIntegrationTest.php
@@ -27,6 +27,7 @@ public function testToolbarToggling() {
     ]);
     $this->drupalLogin($admin_user);
 
+    // Set size for horizontal toolbar.
     $this->getSession()->resizeWindow(1200, 600);
     $this->drupalGet('<front>');
     $this->assertNotEmpty($this->assertSession()->waitForElement('css', 'body.toolbar-horizontal'));
diff --git a/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxCallbacksTest.php b/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxCallbacksTest.php
index 689becedeb..ffdbd98eb9 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxCallbacksTest.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxCallbacksTest.php
@@ -17,23 +17,28 @@ class AjaxCallbacksTest extends WebDriverTestBase {
   public static $modules = ['ajax_forms_test'];
 
   /**
-   * Tests if Ajax callback works on date/datetime elements.
+   * Tests if Ajax callback works on date element.
    */
   public function testDateAjaxCallback() {
-    $this->drupalGet('ajax_forms_test_ajax_element_form');
-    $session = $this->getSession();
-    $assert = $this->assertSession();
 
     // Test Ajax callback when date changes.
-    $this->assertNotEmpty($session->getPage()->find('xpath', '//div[@id="ajax_date_value"][text()="No date yet selected"]'));
-    $session->executeScript('jQuery("[data-drupal-selector=edit-date]").val("2016-01-01").trigger("change");');
-    $this->assertNotEmpty($assert->waitForElement('xpath', '//div[@id="ajax_date_value"]/div[text()="2016-01-01"]'));
+    $this->drupalGet('ajax_forms_test_ajax_element_form');
+    $this->assertNotEmpty($this->getSession()->getPage()->find('xpath', '//div[@id="ajax_date_value"][text()="No date yet selected"]'));
+    $this->getSession()->executeScript('jQuery("[data-drupal-selector=edit-date]").val("2016-01-01").trigger("change");');
+    $this->assertNotEmpty($this->assertSession()->waitForElement('xpath', '//div[@id="ajax_date_value"]/div[text()="2016-01-01"]'));
+  }
+
+  /**
+   * Tests if Ajax callback works on datetime element.
+   */
+  public function testDateTimeAjaxCallback() {
 
     // Test Ajax callback when datetime changes.
-    $this->assertNotEmpty($session->getPage()->find('xpath', '//div[@id="ajax_datetime_value"][text()="No datetime selected."]'));
-    $session->executeScript('jQuery("[data-drupal-selector=edit-datetime-date]").val("2016-01-01");');
-    $session->executeScript('jQuery("[data-drupal-selector=edit-datetime-time]").val("12:00:00").trigger("change");');
-    $this->assertNotEmpty($assert->waitForElement('xpath', '//div[@id="ajax_datetime_value"]/div[text()="2016-01-01 12:00:00"]'));
+    $this->drupalGet('ajax_forms_test_ajax_element_form');
+    $this->assertNotEmpty($this->getSession()->getPage()->find('xpath', '//div[@id="ajax_datetime_value"][text()="No datetime selected."]'));
+    $this->getSession()->executeScript('jQuery("[data-drupal-selector=edit-datetime-date]").val("2016-01-01");');
+    $this->getSession()->executeScript('jQuery("[data-drupal-selector=edit-datetime-time]").val("12:00:00").trigger("change");');
+    $this->assertNotEmpty($this->assertSession()->waitForElement('xpath', '//div[@id="ajax_datetime_value"]/div[text()="2016-01-01 12:00:00"]'));
   }
 
 }
diff --git a/core/tests/Drupal/FunctionalJavascriptTests/DrupalSelenium2Driver.php b/core/tests/Drupal/FunctionalJavascriptTests/DrupalSelenium2Driver.php
index 5200213894..97204a65fd 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/DrupalSelenium2Driver.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/DrupalSelenium2Driver.php
@@ -41,53 +41,4 @@ public function setCookie($name, $value = NULL) {
     $this->getWebDriverSession()->setCookie($cookieArray);
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function dragTo($sourceXpath, $destinationXpath) {
-    $wdSession = $this->getWebDriverSession();
-
-    $wdSession->moveto([
-      'element' => $wdSession->element('xpath', $sourceXpath)->getID()
-    ]);
-
-    $script = <<<JS
-(function (element) {
-    var event = document.createEvent("HTMLEvents");
-
-    event.initEvent("dragstart", true, true);
-    event.dataTransfer = {};
-
-    element.dispatchEvent(event);
-}({{ELEMENT}}));
-JS;
-    $this->withSyn()->executeJsOnXpath($sourceXpath, $script);
-
-    $wdSession->buttondown();
-    $wdSession->moveto([
-      'element' => $wdSession->element('xpath', $destinationXpath)->getID()
-    ]);
-    $wdSession->buttonup();
-
-    $script = <<<JS
-(function (element) {
-    var event = document.createEvent("HTMLEvents");
-
-    event.initEvent("drop", true, true);
-    event.dataTransfer = {};
-
-    element.dispatchEvent(event);
-}({{ELEMENT}}));
-JS;
-    $retries = 0;
-    while ($retries < 3) {
-      try {
-        $this->withSyn()->executeJsOnXpath($destinationXpath, $script);
-        break;
-      }
-      catch (Exception\StaleElementReference $e) {
-        $retries++;
-      }
-    }
-  }
 }
diff --git a/core/tests/Drupal/FunctionalJavascriptTests/WebDriverCurlService.php b/core/tests/Drupal/FunctionalJavascriptTests/WebDriverCurlService.php
index c8eb385088..ea98c938cf 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/WebDriverCurlService.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/WebDriverCurlService.php
@@ -28,7 +28,7 @@ public function execute($requestMethod, $url, $parameters = NULL, $extraOptions
       CURLOPT_FAILONERROR => TRUE,
     ];
     $retries = 0;
-    while ($retries < 5) {
+    while ($retries < 10) {
       try {
         $customHeaders = [
           'Content-Type: application/json;charset=UTF-8',
@@ -98,7 +98,7 @@ public function execute($requestMethod, $url, $parameters = NULL, $extraOptions
 
         $result = json_decode($rawResult, TRUE);
         if (isset($result['status']) && $result['status'] === WebDriverException::STALE_ELEMENT_REFERENCE) {
-          usleep(rand(100000, 1000000));
+          usleep(100000);
           $retries++;
           continue;
         }
diff --git a/core/tests/Drupal/Tests/BrowserTestBase.php b/core/tests/Drupal/Tests/BrowserTestBase.php
index 8d6715e373..065dedccb1 100644
--- a/core/tests/Drupal/Tests/BrowserTestBase.php
+++ b/core/tests/Drupal/Tests/BrowserTestBase.php
@@ -4,7 +4,6 @@
 
 use Behat\Mink\Driver\GoutteDriver;
 use Behat\Mink\Element\Element;
-use Behat\Mink\Exception\ElementNotFoundException;
 use Behat\Mink\Mink;
 use Behat\Mink\Selector\SelectorsHandler;
 use Behat\Mink\Session;
@@ -19,7 +18,6 @@
 use Drupal\Core\Test\TestSetupTrait;
 use Drupal\Core\Url;
 use Drupal\Core\Utility\Error;
-use Drupal\FunctionalJavascriptTests\DrupalSelenium2Driver;
 use Drupal\FunctionalTests\AssertLegacyTrait;
 use Drupal\Tests\block\Traits\BlockCreationTrait;
 use Drupal\Tests\node\Traits\ContentTypeCreationTrait;
@@ -781,12 +779,6 @@ protected function drupalLogin(AccountInterface $account) {
     }
 
     $this->drupalGet('user/login');
-    if ($this->getSession()->getDriver() instanceof DrupalSelenium2Driver) {
-      $page = $this->getSession()->getPage();
-      $page->waitFor(100, function ($page) {
-        return $this->getSession()->getPage()->findField('edit-pass') && $this->getSession()->getPage()->findField('edit-name') && $this->getSession()->getPage()->findButton('Log in');
-      });
-    }
 
     $this->submitForm([
       'name' => $account->getUsername(),