diff --git a/tests/Browser/Browser.php b/tests/Browser/Browser.php
index 03fe8d195..8ba3d93e6 100644
--- a/tests/Browser/Browser.php
+++ b/tests/Browser/Browser.php
@@ -142,6 +142,26 @@ class Browser extends \Laravel\Dusk\Browser
         return !self::isPhone() && !self::isTablet();
     }
 
+    /**
+     * Handler for actions that expect to open a new window
+     *
+     * @param callback $callback Function to execute with Browser object as argument
+     *
+     * @return array Main window handle and new window handle
+     */
+    public function openWindow($callback)
+    {
+        $current_window = $this->driver->getWindowHandle();
+        $before_handles = $this->driver->getWindowHandles();
+
+        $callback($this);
+
+        $after_handles = $this->driver->getWindowHandles();
+        $new_window = reset(array_diff($after_handles, $before_handles));
+
+        return [$current_window, $new_window];
+    }
+
     /**
      * Change state of the Elastic's pretty checkbox
      */
diff --git a/tests/Browser/Components/App.php b/tests/Browser/Components/App.php
index 76ce633f9..7b863ab28 100644
--- a/tests/Browser/Components/App.php
+++ b/tests/Browser/Components/App.php
@@ -2,11 +2,11 @@
 
 namespace Tests\Browser\Components;
 
-use Laravel\Dusk\Component as BaseComponent;
+use Laravel\Dusk\Component;
 use PHPUnit\Framework\Assert;
 use Tests\Browser\Browser;
 
-class App extends BaseComponent
+class App extends Component
 {
     /**
      * Get the root selector for the component.
@@ -46,10 +46,21 @@ class App extends BaseComponent
 
     /**
      * Assert value of rcmail.env entry
+     *
+     * @param Browser      $browser  Browser object
+     * @param array|string $key      Env key name or array of key->expected pairs
+     * @param mixed        $expected Expected value when $key is a string
      */
-    public function assertEnv($browser, string $key, $expected)
+    public function assertEnv($browser, $key, $expected = null)
     {
-        Assert::assertEquals($expected, $this->getEnv($browser, $key));
+        if (is_array($key)) {
+            foreach ($key as $name => $expected) {
+                Assert::assertEquals($expected, $this->getEnv($browser, $name));
+            }
+        }
+        else {
+            Assert::assertEquals($expected, $this->getEnv($browser, $key));
+        }
     }
 
     /**
@@ -69,10 +80,7 @@ class App extends BaseComponent
      */
     public function getEnv($browser, $key)
     {
-        $result = $browser->script("return rcmail.env['$key']");
-        $result = $result[0];
-
-        return $result;
+        return $browser->driver->executeScript("return rcmail.env['$key']");
     }
 
     /**
@@ -80,10 +88,7 @@ class App extends BaseComponent
      */
     public function getObjects($browser)
     {
-        $objects = $browser->script("var i, r = []; for (i in rcmail.gui_objects) r.push(i); return r");
-        $objects = $objects[0];
-
-        return (array) $objects;
+        return (array) $browser->driver->executeScript("var i, r = []; for (i in rcmail.gui_objects) r.push(i); return r");
     }
 
     /**
diff --git a/tests/Browser/Components/Popupmenu.php b/tests/Browser/Components/Popupmenu.php
new file mode 100644
index 000000000..88db19177
--- /dev/null
+++ b/tests/Browser/Components/Popupmenu.php
@@ -0,0 +1,119 @@
+<?php
+
+namespace Tests\Browser\Components;
+
+use Tests\Browser\Browser;
+use Laravel\Dusk\Component;
+
+class Popupmenu extends Component
+{
+    public $id;
+
+    /**
+     * Class constructor
+     */
+    public function __construct($id)
+    {
+        $this->id = $id;
+    }
+
+    /**
+     * Get the root selector for the component.
+     *
+     * @return string
+     */
+    public function selector()
+    {
+        return '#' . $this->id;
+    }
+
+    /**
+     * Assert that the browser page contains the component.
+     *
+     * @param Browser $browser
+     *
+     * @return void
+     */
+    public function assert($browser)
+    {
+        $browser->waitFor($this->selector());
+    }
+
+    /**
+     * Get the element shortcuts for the component.
+     *
+     * @return array
+     */
+    public function elements()
+    {
+        return [
+        ];
+    }
+
+    /**
+     * Assert popup menu state
+     */
+    public function assertMenuState($browser, $active, $disabled = [], $missing = [])
+    {
+        foreach ($active as $option) {
+            // Print action is disabled on phones
+            if ($option == 'print' && $browser->isPhone()) {
+                $browser->assertMissing("a.print");
+            }
+            else {
+                $browser->assertVisible("a.{$option}:not(.disabled)");
+            }
+        }
+
+        foreach ($disabled as $option) {
+            if ($option == 'print' && $browser->isPhone()) {
+                $browser->assertMissing("a.print");
+            }
+            else {
+                $browser->assertVisible("a.{$option}.disabled");
+            }
+        }
+
+        foreach ($missing as $option) {
+            $browser->assertMissing("a.{$option}");
+        }
+    }
+
+    /**
+     * Close popup menu
+     */
+    public function closeMenu($browser)
+    {
+        // hide the menu back
+        $browser->withinBody(function ($browser) {
+            $browser->script("window.UI.menu_hide('{$this->id}')");
+            $browser->waitUntilMissing($this->selector());
+            if ($browser->isPhone()) {
+                // FIXME: For some reason sometimes .popover-overlay does not close,
+                //        we have to remove it manually
+                $browser->script(
+                    "Array.from(document.getElementsByClassName('popover-overlay')).forEach(function(elem) { elem.parentNode.removeChild(elem); })"
+                );
+            }
+        });
+    }
+
+    /**
+     * Select popup menu item
+     */
+    public function clickMenuItem($browser, $name, $dropdown_action = null)
+    {
+        $selector = "a.{$name}" . ($dropdown_action ? " + a.dropdown" : '');
+
+        $browser->click($selector);
+
+        if ($dropdown_action) {
+            $popup_id = $browser->attribute($selector, 'data-popup');
+            $browser->withinBody(function ($browser) use ($popup_id, $dropdown_action) {
+                $browser->click("#{$popup_id} li a.{$dropdown_action}");
+            });
+        }
+
+        $this->closeMenu($browser);
+    }
+}
diff --git a/tests/Browser/Components/Taskmenu.php b/tests/Browser/Components/Taskmenu.php
index 499f8ca59..dbd84fefb 100644
--- a/tests/Browser/Components/Taskmenu.php
+++ b/tests/Browser/Components/Taskmenu.php
@@ -3,9 +3,9 @@
 namespace Tests\Browser\Components;
 
 use Tests\Browser\Browser;
-use Laravel\Dusk\Component as BaseComponent;
+use Laravel\Dusk\Component;
 
-class Taskmenu extends BaseComponent
+class Taskmenu extends Component
 {
     protected $options = ['compose', 'mail', 'contacts', 'settings', 'about', 'logout'];
 
diff --git a/tests/Browser/Components/Toolbarmenu.php b/tests/Browser/Components/Toolbarmenu.php
index 376e162be..f49f780b4 100644
--- a/tests/Browser/Components/Toolbarmenu.php
+++ b/tests/Browser/Components/Toolbarmenu.php
@@ -3,9 +3,9 @@
 namespace Tests\Browser\Components;
 
 use Tests\Browser\Browser;
-use Laravel\Dusk\Component as BaseComponent;
+use Laravel\Dusk\Component;
 
-class Toolbarmenu extends BaseComponent
+class Toolbarmenu extends Component
 {
     /**
      * Get the root selector for the component.
diff --git a/tests/Browser/Mail/Mail.php b/tests/Browser/Mail/Mail.php
index 8c7806ca6..abfe6963b 100644
--- a/tests/Browser/Mail/Mail.php
+++ b/tests/Browser/Mail/Mail.php
@@ -3,6 +3,7 @@
 namespace Tests\Browser\Mail;
 
 use Tests\Browser\Components\App;
+use Tests\Browser\Components\Popupmenu;
 
 class Mail extends \Tests\Browser\TestCase
 {
@@ -53,4 +54,31 @@ class Mail extends \Tests\Browser\TestCase
             $browser->assertTaskMenu('mail');
         });
     }
+
+    /**
+     * Test message menu
+     */
+    public function testMessageMenu()
+    {
+        $this->browse(function ($browser) {
+            $browser->go('mail');
+
+            $browser->clickToolbarMenuItem('more');
+
+            $browser->with(new Popupmenu('message-menu'), function ($browser) {
+                // Note: These are button class names, not action names
+                $active = ['import'];
+                $disabled = ['print', 'download', 'edit.asnew', 'source', 'move', 'copy', 'extwin'];
+                $hidden = [];
+
+                if ($browser->isPhone()) {
+                    $hidden = ['print', 'extwin'];
+                    $disabled = array_diff($disabled, $hidden);
+                }
+
+                $browser->assertMenuState($active, $disabled, $hidden);
+                $browser->closeMenu();
+            });
+        });
+    }
 }
diff --git a/tests/Browser/Mail/Open.php b/tests/Browser/Mail/Open.php
new file mode 100644
index 000000000..972e0bcc6
--- /dev/null
+++ b/tests/Browser/Mail/Open.php
@@ -0,0 +1,70 @@
+<?php
+
+namespace Tests\Browser\Mail;
+
+use Tests\Browser\Components\App;
+use Tests\Browser\Components\Popupmenu;
+
+class Open extends \Tests\Browser\TestCase
+{
+    protected function setUp()
+    {
+        parent::setUp();
+
+        \bootstrap::init_imap();
+        \bootstrap::purge_mailbox('INBOX');
+
+        // import email messages
+        foreach (glob(TESTS_DIR . 'data/mail/list_00.eml') as $f) {
+            \bootstrap::import_message($f, 'INBOX');
+        }
+    }
+
+    /**
+     * Test Open in New Window action
+     */
+    public function testOpenInNewWindow()
+    {
+        $this->browse(function ($browser) {
+            if ($browser->isPhone()) {
+                $this->markTestSkipped();
+                return;
+            }
+
+            $browser->go('mail');
+
+            $browser->waitFor('#messagelist tbody tr:first-child')
+                ->ctrlClick('#messagelist tbody tr:first-child');
+
+            $browser->clickToolbarMenuItem('more');
+
+            $browser->with(new Popupmenu('message-menu'), function ($browser) {
+                $uids = $browser->driver->executeScript('return rcmail.message_list.get_selection()');
+
+                $this->assertCount(1, $uids);
+                $this->assertTrue(is_int($uids[0]) && $uids[0] > 0);
+
+                $uid = $uids[0];
+
+                list($current_window, $new_window) = $browser->openWindow(function ($browser) {
+                    $browser->clickMenuItem('extwin');
+                });
+
+                $browser->driver->switchTo()->window($new_window);
+
+                $browser->with(new App(), function ($browser) use ($uid) {
+                    $browser->assertEnv([
+                            'task' => 'mail',
+                            'action' => 'show',
+                            'uid' => $uid,
+                    ]);
+
+                    // TODO: werify the toolbar, which is different here than in the preview frame
+                });
+
+                $browser->driver->close();
+                $browser->driver->switchTo()->window($current_window);
+            });
+        });
+    }
+}
diff --git a/tests/Browser/bootstrap.php b/tests/Browser/bootstrap.php
index 49db75944..118f3502b 100644
--- a/tests/Browser/bootstrap.php
+++ b/tests/Browser/bootstrap.php
@@ -34,6 +34,7 @@ define('TESTS_PASS', $rcmail->config->get('tests_password'));
 require_once(__DIR__ . '/Browser.php');
 require_once(__DIR__ . '/TestCase.php');
 require_once(__DIR__ . '/Components/App.php');
+require_once(__DIR__ . '/Components/Popupmenu.php');
 require_once(__DIR__ . '/Components/Taskmenu.php');
 require_once(__DIR__ . '/Components/Toolbarmenu.php');
 
diff --git a/tests/Browser/phpunit.xml b/tests/Browser/phpunit.xml
index 3c31c2d80..b3ec82607 100644
--- a/tests/Browser/phpunit.xml
+++ b/tests/Browser/phpunit.xml
@@ -25,6 +25,7 @@
             <file>Mail/Compose.php</file>
             <file>Mail/Getunread.php</file>
             <file>Mail/List.php</file>
+            <file>Mail/Open.php</file>
         </testsuite>
     </testsuites>
 </phpunit>