accessibility

SafeExamBrowser.Browser.Contracts/IBrowserApplication.cs

@@ -6,8 +6,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System;
 using SafeExamBrowser.Applications.Contracts;
 using SafeExamBrowser.Browser.Contracts.Events;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 
 namespace SafeExamBrowser.Browser.Contracts
 {
@@ -30,5 +32,15 @@ namespace SafeExamBrowser.Browser.Contracts
 		/// Event fired when the browser application detects a request to terminate SEB.
 		/// </summary>
 		event TerminationRequestedEventHandler TerminationRequested;
+
+		/// <summary>
+		/// Event fired when the user tries to focus the taskbar.
+		/// </summary>
+		event LoseFocusRequestedEventHandler LoseFocusRequested;
+
+		/// <summary>
+		/// Transfers the focus to the browser window.
+		/// </summary>
+		void Focus(bool forward);
 	}
 }

SafeExamBrowser.Browser.Contracts/SafeExamBrowser.Browser.Contracts.csproj

@@ -75,6 +75,10 @@
       <Project>{30b2d907-5861-4f39-abad-c4abf1b3470e}</Project>
       <Name>SafeExamBrowser.Settings</Name>
     </ProjectReference>
+    <ProjectReference Include="..\SafeExamBrowser.UserInterface.Contracts\SafeExamBrowser.UserInterface.Contracts.csproj">
+      <Project>{c7889e97-6ff6-4a58-b7cb-521ed276b316}</Project>
+      <Name>SafeExamBrowser.UserInterface.Contracts</Name>
+    </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
 </Project>

SafeExamBrowser.Browser/BrowserApplication.cs

@@ -27,6 +27,7 @@ using SafeExamBrowser.Logging.Contracts;
 using SafeExamBrowser.Settings.Browser.Proxy;
 using SafeExamBrowser.Settings.Logging;
 using SafeExamBrowser.UserInterface.Contracts;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.FileSystemDialog;
 using SafeExamBrowser.UserInterface.Contracts.MessageBox;
 using SafeExamBrowser.WindowsApi.Contracts;
@@ -58,6 +59,7 @@ namespace SafeExamBrowser.Browser
 
 		public event DownloadRequestedEventHandler ConfigurationDownloadRequested;
 		public event SessionIdentifierDetectedEventHandler SessionIdentifierDetected;
+		public event LoseFocusRequestedEventHandler LoseFocusRequested;
 		public event TerminationRequestedEventHandler TerminationRequested;
 		public event WindowsChangedEventHandler WindowsChanged;
 
@@ -195,6 +197,7 @@ namespace SafeExamBrowser.Browser
 			window.ResetRequested += Window_ResetRequested;
 			window.SessionIdentifierDetected += (i) => SessionIdentifierDetected?.Invoke(i);
 			window.TerminationRequested += () => TerminationRequested?.Invoke();
+			window.LoseFocusRequested += (forward) => LoseFocusRequested?.Invoke(forward);
 
 			window.InitializeControl();
 			windows.Add(window);
@@ -457,5 +460,13 @@ namespace SafeExamBrowser.Browser
 			CreateNewWindow();
 			logger.Info("Successfully reset browser.");
 		}
+
+		public void Focus(bool forward)
+		{
+			windows.ForEach(window =>
+			{
+				window.Focus(forward);
+			});
+		}
 	}
 }

SafeExamBrowser.Browser/BrowserControl.cs

@@ -143,5 +143,14 @@ namespace SafeExamBrowser.Browser
 		{
 			control.BrowserCore.SetZoomLevel(level);
 		}
+
+		/// <summary>
+		/// Executes the given Javascript code in the browser.
+		/// </summary>
+		public async void ExecuteJavascript(string javascript, System.Action<dynamic> callback)
+		{
+			var result = await this.control.EvaluateScriptAsync(javascript);
+			callback(result);
+		}
 	}
 }

SafeExamBrowser.Browser/BrowserWindow.cs

@@ -31,6 +31,7 @@ using SafeExamBrowser.Settings.Browser.Filter;
 using SafeExamBrowser.UserInterface.Contracts;
 using SafeExamBrowser.UserInterface.Contracts.Browser;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Data;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.FileSystemDialog;
 using SafeExamBrowser.UserInterface.Contracts.MessageBox;
 using Syroot.Windows.IO;
@@ -80,6 +81,7 @@ namespace SafeExamBrowser.Browser
 		internal event PopupRequestedEventHandler PopupRequested;
 		internal event ResetRequestedEventHandler ResetRequested;
 		internal event SessionIdentifierDetectedEventHandler SessionIdentifierDetected;
+		internal event LoseFocusRequestedEventHandler LoseFocusRequested;
 		internal event TerminationRequestedEventHandler TerminationRequested;
 
 		public event IconChangedEventHandler IconChanged;
@@ -162,6 +164,7 @@ namespace SafeExamBrowser.Browser
 			keyboardHandler.ZoomInRequested += ZoomInRequested;
 			keyboardHandler.ZoomOutRequested += ZoomOutRequested;
 			keyboardHandler.ZoomResetRequested += ZoomResetRequested;
+			keyboardHandler.TabPressed += TabPressed;
 			resourceHandler.SessionIdentifierDetected += (id) => SessionIdentifierDetected?.Invoke(id);
 			requestHandler.QuitUrlVisited += RequestHandler_QuitUrlVisited;
 			requestHandler.RequestBlocked += RequestHandler_RequestBlocked;
@@ -198,6 +201,7 @@ namespace SafeExamBrowser.Browser
 			window.FindRequested += Window_FindRequested;
 			window.ForwardNavigationRequested += Window_ForwardNavigationRequested;
 			window.HomeNavigationRequested += HomeNavigationRequested;
+			window.LoseFocusRequested += Window_LoseFocusRequested;
 			window.ReloadRequested += ReloadRequested;
 			window.ZoomInRequested += ZoomInRequested;
 			window.ZoomOutRequested += ZoomOutRequested;
@@ -655,6 +659,11 @@ namespace SafeExamBrowser.Browser
 			Control.NavigateForwards();
 		}
 
+		private void Window_LoseFocusRequested(bool forward)
+		{
+			LoseFocusRequested?.Invoke(forward);
+		}
+
 		private void ZoomInRequested()
 		{
 			if (settings.AllowPageZoom && CalculateZoomPercentage() < 300)
@@ -688,6 +697,43 @@ namespace SafeExamBrowser.Browser
 			}
 		}
 
+		private void TabPressed(object sender, bool shiftPressed)
+		{
+			this.Control.ExecuteJavascript("document.activeElement.tagName", result =>
+			{
+				var tagName = result.Result as string;
+				if (tagName != null)
+				{
+					if (tagName.ToUpper() == "BODY")
+					{
+						// this means the user is now at the start of the focus / tabIndex chain in the website
+						if (shiftPressed)
+						{
+							window.FocusToolbar(!shiftPressed);
+						}
+						else
+						{
+							this.LoseFocusRequested?.Invoke(true);
+						}
+					}
+				}
+			});
+		}
+
+		internal void Focus(bool forward)
+		{
+			if (forward)
+			{
+				window.FocusToolbar(forward);
+			}
+			else
+			{
+				window.FocusBrowser();
+
+				this.Activate();
+			}
+		}
+
 		private double CalculateZoomPercentage()
 		{
 			return (zoomLevel * 25.0) + 100.0;

SafeExamBrowser.Browser/Handlers/KeyboardHandler.cs

@@ -20,6 +20,9 @@ namespace SafeExamBrowser.Browser.Handlers
 		internal event ActionRequestedEventHandler ZoomInRequested;
 		internal event ActionRequestedEventHandler ZoomOutRequested;
 		internal event ActionRequestedEventHandler ZoomResetRequested;
+		internal event System.EventHandler<bool> TabPressed;
+
+		private int? currentKeyDown = null;
 
 		public bool OnKeyEvent(IWebBrowser browserControl, IBrowser browser, KeyType type, int keyCode, int nativeKeyCode, CefEventFlags modifiers, bool isSystemKey)
 		{
@@ -52,8 +55,14 @@ namespace SafeExamBrowser.Browser.Handlers
 				{
 					ZoomResetRequested?.Invoke();
 				}
+
+				if (keyCode == (int)Keys.Tab && keyCode == currentKeyDown)
+				{
+					TabPressed?.Invoke(this, shift);
+				}
 			}
 
+			currentKeyDown = null;
 			return false;
 		}
 
@@ -66,6 +75,11 @@ namespace SafeExamBrowser.Browser.Handlers
 				return true;
 			}
 
+			if (type == KeyType.RawKeyDown || type == KeyType.KeyDown)
+			{
+				currentKeyDown = keyCode;
+			}
+
 			return false;
 		}
 	}

SafeExamBrowser.Client/ClientController.cs

@@ -188,6 +188,7 @@ namespace SafeExamBrowser.Client
 			Browser.ConfigurationDownloadRequested += Browser_ConfigurationDownloadRequested;
 			Browser.SessionIdentifierDetected += Browser_SessionIdentifierDetected;
 			Browser.TerminationRequested += Browser_TerminationRequested;
+			Browser.LoseFocusRequested += Browser_LoseFocusRequested; ;
 			ClientHost.ExamSelectionRequested += ClientHost_ExamSelectionRequested;
 			ClientHost.MessageBoxRequested += ClientHost_MessageBoxRequested;
 			ClientHost.PasswordRequested += ClientHost_PasswordRequested;
@@ -198,6 +199,7 @@ namespace SafeExamBrowser.Client
 			displayMonitor.DisplayChanged += DisplayMonitor_DisplaySettingsChanged;
 			runtime.ConnectionLost += Runtime_ConnectionLost;
 			systemMonitor.SessionSwitched += SystemMonitor_SessionSwitched;
+			taskbar.LoseFocusRequested += Taskbar_LoseFocusRequested;
 			taskbar.QuitButtonClicked += Shell_QuitButtonClicked;
 
 			foreach (var activator in context.Activators.OfType<ITerminationActivator>())
@@ -211,6 +213,16 @@ namespace SafeExamBrowser.Client
 			}
 		}
 
+		private void Taskbar_LoseFocusRequested(bool forward)
+		{
+			this.Browser.Focus(forward);
+		}
+
+		private void Browser_LoseFocusRequested(bool forward)
+		{
+			this.taskbar.Focus(forward);
+		}
+
 		private void DeregisterEvents()
 		{
 			actionCenter.QuitButtonClicked -= Shell_QuitButtonClicked;

SafeExamBrowser.UserInterface.Contracts/Browser/IBrowserControl.cs

@@ -61,6 +61,11 @@ namespace SafeExamBrowser.UserInterface.Contracts.Browser
 		/// </summary>
 		void Destroy();
 
+		/// <summary>
+		/// Executes the given Javascript code in the browser.
+		/// </summary>
+		void ExecuteJavascript(string javascript, System.Action<dynamic> callback);
+
 		/// <summary>
 		/// Attempts to find the given term on the current page according to the specified parameters.
 		/// </summary>

SafeExamBrowser.UserInterface.Contracts/Browser/IBrowserWindow.cs

@@ -10,6 +10,7 @@ using System;
 using SafeExamBrowser.Core.Contracts.Resources.Icons;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Data;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Events;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.Windows;
 
 namespace SafeExamBrowser.UserInterface.Contracts.Browser
@@ -64,6 +65,11 @@ namespace SafeExamBrowser.UserInterface.Contracts.Browser
 		/// </summary>
 		event ActionRequestedEventHandler HomeNavigationRequested;
 
+		/// <summary>
+		/// Event fired when the browser window wants to lose focus to the taskbar.
+		/// </summary>
+		event LoseFocusRequestedEventHandler LoseFocusRequested;
+
 		/// <summary>
 		/// Event fired when the user would like to reload the current page.
 		/// </summary>
@@ -123,5 +129,16 @@ namespace SafeExamBrowser.UserInterface.Contracts.Browser
 		/// Updates the display value of the current page zoom. Value is expected to be in percentage.
 		/// </summary>
 		void UpdateZoomLevel(double value);
+
+		/// <summary>
+		/// Sets the focus to the toolbar.
+		/// </summary>
+		/// <param name="forward">If true, the first focusable control on the toolbar gets focused. If false, the last one.</param>
+		void FocusToolbar(bool forward);
+
+		/// <summary>
+		/// Sets the focus to the browser.
+		/// </summary>
+		void FocusBrowser();
 	}
 }

SafeExamBrowser.UserInterface.Contracts/Events/LoseFocusRequestedEventHandler.cs

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2021 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+namespace SafeExamBrowser.UserInterface.Contracts.Events
+{
+	/// <summary>
+	/// Event handler used to indicate that the user wants to move the focus away from the item.
+	/// </summary>
+	public delegate void LoseFocusRequestedEventHandler(bool forward);
+}

SafeExamBrowser.UserInterface.Contracts/SafeExamBrowser.UserInterface.Contracts.csproj

@@ -63,6 +63,7 @@
     <Compile Include="Browser\IBrowserControl.cs" />
     <Compile Include="Browser\IBrowserWindow.cs" />
     <Compile Include="Events\ActionRequestedEventHandler.cs" />
+    <Compile Include="Events\LoseFocusRequestedEventHandler.cs" />
     <Compile Include="FileSystemDialog\FileSystemDialogResult.cs" />
     <Compile Include="FileSystemDialog\FileSystemElement.cs" />
     <Compile Include="FileSystemDialog\FileSystemOperation.cs" />

SafeExamBrowser.UserInterface.Contracts/Shell/ITaskbar.cs

@@ -7,6 +7,7 @@
  */
 
 using SafeExamBrowser.I18n.Contracts;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.Shell.Events;
 
 namespace SafeExamBrowser.UserInterface.Contracts.Shell
@@ -31,6 +32,11 @@ namespace SafeExamBrowser.UserInterface.Contracts.Shell
 		/// </summary>
 		event QuitButtonClickedEventHandler QuitButtonClicked;
 
+		/// <summary>
+		/// Event fired when the Taskbar wants to lose focus.
+		/// </summary>
+		event LoseFocusRequestedEventHandler LoseFocusRequested;
+
 		/// <summary>
 		/// Adds the given application control to the taskbar.
 		/// </summary>
@@ -70,5 +76,10 @@ namespace SafeExamBrowser.UserInterface.Contracts.Shell
 		/// Shows the taskbar.
 		/// </summary>
 		void Show();
+
+		/// <summary>
+		/// Puts the focus on the taskbar.
+		/// </summary>
+		void Focus(bool forward = true);
 	}
 }

SafeExamBrowser.UserInterface.Desktop/Windows/BrowserWindow.xaml.cs

@@ -16,11 +16,13 @@ using System.Windows.Interop;
 using System.Windows.Media.Imaging;
 using SafeExamBrowser.Core.Contracts.Resources.Icons;
 using SafeExamBrowser.I18n.Contracts;
+using SafeExamBrowser.Logging.Contracts;
 using SafeExamBrowser.Settings.Browser;
 using SafeExamBrowser.UserInterface.Contracts;
 using SafeExamBrowser.UserInterface.Contracts.Browser;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Data;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Events;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.Windows;
 using SafeExamBrowser.UserInterface.Contracts.Windows.Events;
 using SafeExamBrowser.UserInterface.Desktop.Controls.Browser;
@@ -36,6 +38,7 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 
 		private WindowClosedEventHandler closed;
 		private WindowClosingEventHandler closing;
+		private bool browserControlGetsFocusFromTaskbar = false;
 
 		private WindowSettings WindowSettings
 		{
@@ -56,6 +59,7 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 		public event ActionRequestedEventHandler ZoomInRequested;
 		public event ActionRequestedEventHandler ZoomOutRequested;
 		public event ActionRequestedEventHandler ZoomResetRequested;
+		public event LoseFocusRequestedEventHandler LoseFocusRequested;
 
 		event WindowClosedEventHandler IWindow.Closed
 		{
@@ -199,6 +203,26 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 			}
 		}
 
+		private void BrowserWindow_KeyDown(object sender, KeyEventArgs e)
+		{
+			if (e.Key == Key.Tab && Toolbar.IsKeyboardFocusWithin)
+			{
+				if ((Keyboard.Modifiers & ModifierKeys.Shift) == ModifierKeys.Shift)
+				{
+					var firstActiveElementInToolbar = Toolbar.PredictFocus(FocusNavigationDirection.Right);
+					if (firstActiveElementInToolbar is System.Windows.UIElement)
+					{
+						var control = firstActiveElementInToolbar as System.Windows.UIElement;
+						if (control.IsKeyboardFocusWithin)
+						{
+							this.LoseFocusRequested?.Invoke(false);
+							e.Handled = true;
+						}
+					}
+				}
+			}
+		}
+
 		private void BrowserWindow_KeyUp(object sender, KeyEventArgs e)
 		{
 			if (e.Key == Key.F5)
@@ -215,6 +239,21 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 			{
 				ShowFindbar();
 			}
+
+			if (e.Key == Key.Tab)
+			{
+				if (BrowserControlHost.IsFocused && (Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control)
+				{
+					if (Findbar.Visibility == Visibility.Hidden || (Keyboard.Modifiers & ModifierKeys.Shift) == ModifierKeys.Shift)
+					{
+						Toolbar.Focus();
+					}
+					else if (Toolbar.Visibility == Visibility.Hidden)
+					{
+						Findbar.Focus();
+					}
+				}
+			}
 		}
 
 		private void BrowserWindow_Loaded(object sender, RoutedEventArgs e)
@@ -324,6 +363,7 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 			MenuButton.MouseLeave += (o, args) => Task.Delay(250).ContinueWith(_ => Dispatcher.Invoke(() => MenuPopup.IsOpen = MenuPopup.IsMouseOver));
 			MenuPopup.CustomPopupPlacementCallback = new CustomPopupPlacementCallback(Popup_PlacementCallback);
 			MenuPopup.MouseLeave += (o, args) => Task.Delay(250).ContinueWith(_ => Dispatcher.Invoke(() => MenuPopup.IsOpen = MenuPopup.IsMouseOver));
+			KeyDown += BrowserWindow_KeyDown;
 			KeyUp += BrowserWindow_KeyUp;
 			LocationChanged += (o, args) => { DownloadsPopup.IsOpen = false; MenuPopup.IsOpen = false; };
 			ReloadButton.Click += (o, args) => ReloadRequested?.Invoke();
@@ -338,6 +378,41 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 			ZoomInButton.Click += (o, args) => ZoomInRequested?.Invoke();
 			ZoomOutButton.Click += (o, args) => ZoomOutRequested?.Invoke();
 			ZoomResetButton.Click += (o, args) => ZoomResetRequested?.Invoke();
+			BrowserControlHost.GotKeyboardFocus += BrowserControlHost_GotKeyboardFocus;
+		}
+
+		private void BrowserControlHost_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
+		{
+			var forward = !this.browserControlGetsFocusFromTaskbar;
+
+			// focus the first / last element on the page
+			var javascript = @"
+if (typeof __SEB_focusElement === 'undefined') {
+  __SEB_focusElement = function (forward) {
+    var items = [].map
+      .call(document.body.querySelectorAll(['input', 'select', 'a[href]', 'textarea', 'button', '[tabindex]']), function(el, i) { return { el, i } })
+      .filter(function(e) { return e.el.tabIndex >= 0 && !e.el.disabled && e.el.offsetParent; })
+      .sort(function(a,b) { return a.el.tabIndex === b.el.tabIndex ? a.i - b.i : (a.el.tabIndex || 9E9) - (b.el.tabIndex || 9E9); })
+    var item = items[forward ? 1 : items.length - 1];
+    setTimeout(function () { item.focus(); }, 20);
+  }
+}";
+			var control = BrowserControlHost.Child as IBrowserControl;
+			control.ExecuteJavascript(javascript, result =>
+			{
+				if (!result.Success)
+				{
+					//logger.Error($"Javascript error {result.Message}!");
+				}
+			});
+
+			control.ExecuteJavascript("__SEB_focusElement(" + forward.ToString().ToLower() + ")", result =>
+			{
+				if (!result.Success)
+				{
+					//logger.Error($"Javascript error {result.Message}!");
+				}
+			});
 		}
 
 		private void ApplySettings()
@@ -444,5 +519,42 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 			FindMenuText.Text = text.Get(TextKey.BrowserWindow_FindMenuItem);
 			ZoomText.Text = text.Get(TextKey.BrowserWindow_ZoomMenuItem);
 		}
+
+		public void FocusToolbar(bool forward)
+		{
+			this.Dispatcher.BeginInvoke((Action)(async () =>
+			{
+				this.Activate();
+				await Task.Delay(50);
+
+				// focus all elements in the toolbar, such that the last element that is enabled gets focus
+				var buttons = new System.Windows.Controls.Control[] { ForwardButton, BackwardButton, ReloadButton, UrlTextBox, MenuButton, };
+				for (var i = forward ? 0 : buttons.Length - 1; i >= 0 && i < buttons.Length; i += forward ? 1 : -1)
+				{
+					if (buttons[i].IsEnabled && buttons[i].Visibility == Visibility.Visible)
+					{
+						buttons[i].Focus();
+						break;
+					}
+				}
+			}));
+		}
+
+		public void FocusBrowser()
+		{
+			this.Dispatcher.BeginInvoke((Action)(async () =>
+			{
+				this.FocusToolbar(false);
+				await Task.Delay(100);
+
+				this.browserControlGetsFocusFromTaskbar = true;
+
+				var focusedElement = FocusManager.GetFocusedElement(this) as UIElement;
+				focusedElement.MoveFocus(new TraversalRequest(FocusNavigationDirection.Right));
+
+				await Task.Delay(150);
+				this.browserControlGetsFocusFromTaskbar = false;
+			}));
+		}
 	}
 }

SafeExamBrowser.UserInterface.Desktop/Windows/Taskbar.xaml

@@ -6,6 +6,7 @@
         xmlns:local="clr-namespace:SafeExamBrowser.UserInterface.Desktop.Controls.Taskbar"
         xmlns:s="clr-namespace:System;assembly=mscorlib"
         mc:Ignorable="d" Title="Taskbar" Background="{DynamicResource BackgroundBrush}" Height="40" Width="750" WindowStyle="None" Topmost="True"
+        KeyDown="Window_KeyDown" KeyUp="Window_KeyUp"
         ResizeMode="NoResize" Icon="../Images/SafeExamBrowser.ico">
     <Window.Resources>
         <ResourceDictionary>

SafeExamBrowser.UserInterface.Desktop/Windows/Taskbar.xaml.cs

@@ -6,10 +6,12 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System;
 using System.ComponentModel;
 using System.Windows;
 using SafeExamBrowser.I18n.Contracts;
 using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.Shell;
 using SafeExamBrowser.UserInterface.Contracts.Shell.Events;
 using SafeExamBrowser.UserInterface.Shared.Utilities;
@@ -20,6 +22,8 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 	{
 		private bool allowClose;
 		private ILogger logger;
+		private bool isQuitButtonFocusedAtKeyDown;
+		private bool isFirstChildFocusedAtKeyDown;
 
 		public bool ShowClock
 		{
@@ -31,6 +35,7 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 			set { Dispatcher.Invoke(() => QuitButton.Visibility = value ? Visibility.Visible : Visibility.Collapsed); }
 		}
 
+		public event LoseFocusRequestedEventHandler LoseFocusRequested;
 		public event QuitButtonClickedEventHandler QuitButtonClicked;
 
 		internal Taskbar(ILogger logger)
@@ -159,5 +164,82 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 			Loaded += (o, args) => InitializeBounds();
 			QuitButton.Clicked += QuitButton_Clicked;
 		}
+
+		private void Window_KeyDown(object sender, System.Windows.Input.KeyEventArgs e)
+		{
+			this.isQuitButtonFocusedAtKeyDown = this.QuitButton.IsKeyboardFocusWithin;
+			this.isFirstChildFocusedAtKeyDown = this.ApplicationStackPanel.Children[0].IsKeyboardFocusWithin;
+		}
+
+		private void Window_KeyUp(object sender, System.Windows.Input.KeyEventArgs e)
+		{
+			if (e.Key == System.Windows.Input.Key.Tab)
+			{
+				var shift = System.Windows.Input.Keyboard.IsKeyDown(System.Windows.Input.Key.LeftShift);
+				if (!shift && this.ApplicationStackPanel.Children[0].IsKeyboardFocusWithin && this.isQuitButtonFocusedAtKeyDown)
+				{
+					this.LoseFocusRequested?.Invoke(true);
+					e.Handled = true;
+				}
+				else if (shift && this.QuitButton.IsKeyboardFocusWithin && this.isFirstChildFocusedAtKeyDown)
+				{
+					this.LoseFocusRequested?.Invoke(false);
+					e.Handled = true;
+				}
+			}
+
+			this.isQuitButtonFocusedAtKeyDown = false;
+			this.isFirstChildFocusedAtKeyDown = false;
+		}
+
+		void ITaskbar.Focus(bool forward)
+		{
+			this.Dispatcher.BeginInvoke((Action)(() =>
+			{
+				base.Activate();
+				if (forward)
+				{
+					this.SetFocusWithin(this.ApplicationStackPanel.Children[0]);
+				}
+				else
+				{
+					this.QuitButton.Focus();
+				}
+			}));
+		}
+
+		private bool SetFocusWithin(UIElement uIElement)
+		{
+			if (uIElement.Focusable)
+			{
+				uIElement.Focus();
+				return true;
+			}
+
+			if (uIElement is System.Windows.Controls.Panel)
+			{
+				var panel = uIElement as System.Windows.Controls.Panel;
+				for (var i = 0; i < panel.Children.Count; i++)
+				{
+					if (this.SetFocusWithin(panel.Children[i]))
+					{
+						return true;
+					}
+				}
+
+				return false;
+			}
+			else if (uIElement is System.Windows.Controls.ContentControl)
+			{
+				var control = uIElement as System.Windows.Controls.ContentControl;
+				var content = control.Content as UIElement;
+				if (content != null)
+				{
+					return this.SetFocusWithin(content);
+				}
+			}
+
+			return false;
+		}
 	}
 }

SafeExamBrowser.UserInterface.Mobile/Windows/BrowserWindow.xaml.cs

@@ -21,6 +21,7 @@ using SafeExamBrowser.UserInterface.Contracts;
 using SafeExamBrowser.UserInterface.Contracts.Browser;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Data;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Events;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.Windows;
 using SafeExamBrowser.UserInterface.Contracts.Windows.Events;
 using SafeExamBrowser.UserInterface.Mobile.Controls.Browser;
@@ -51,6 +52,7 @@ namespace SafeExamBrowser.UserInterface.Mobile.Windows
 		public event ActionRequestedEventHandler DeveloperConsoleRequested;
 		public event FindRequestedEventHandler FindRequested;
 		public event ActionRequestedEventHandler ForwardNavigationRequested;
+		public event LoseFocusRequestedEventHandler LoseFocusRequested;
 		public event ActionRequestedEventHandler HomeNavigationRequested;
 		public event ActionRequestedEventHandler ReloadRequested;
 		public event ActionRequestedEventHandler ZoomInRequested;
@@ -454,5 +456,20 @@ namespace SafeExamBrowser.UserInterface.Mobile.Windows
 			FindMenuText.Text = text.Get(TextKey.BrowserWindow_FindMenuItem);
 			ZoomText.Text = text.Get(TextKey.BrowserWindow_ZoomMenuItem);
 		}
+
+		public void FocusToolbar(bool forward)
+		{
+			throw new NotImplementedException();
+		}
+
+		public void FocusBrowser()
+		{
+			throw new NotImplementedException();
+		}
+
+		public void Debug()
+		{
+			throw new NotImplementedException();
+		}
 	}
 }

SafeExamBrowser.UserInterface.Mobile/Windows/Taskbar.xaml.cs

@@ -10,6 +10,7 @@ using System.ComponentModel;
 using System.Windows;
 using SafeExamBrowser.I18n.Contracts;
 using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.UserInterface.Contracts.Events;
 using SafeExamBrowser.UserInterface.Contracts.Shell;
 using SafeExamBrowser.UserInterface.Contracts.Shell.Events;
 using SafeExamBrowser.UserInterface.Shared.Utilities;
@@ -31,6 +32,7 @@ namespace SafeExamBrowser.UserInterface.Mobile.Windows
 			set { Dispatcher.Invoke(() => QuitButton.Visibility = value ? Visibility.Visible : Visibility.Collapsed); }
 		}
 
+		public event LoseFocusRequestedEventHandler LoseFocusRequested;
 		public event QuitButtonClickedEventHandler QuitButtonClicked;
 
 		internal Taskbar(ILogger logger)
@@ -159,5 +161,18 @@ namespace SafeExamBrowser.UserInterface.Mobile.Windows
 			Loaded += (o, args) => InitializeBounds();
 			QuitButton.Clicked += QuitButton_Clicked;
 		}
+
+		void ITaskbar.Focus(bool fromTop)
+		{
+			base.Activate();
+			if (fromTop)
+			{
+				this.ApplicationStackPanel.Children[0].Focus();
+			}
+			else
+			{
+				this.QuitButton.Focus();
+			}
+		}
 	}
 }