SEBWIN-312: Ensured system task view is never activated and improved pause mechanism for activators.

SafeExamBrowser.Monitoring/Keyboard/KeyboardInterceptor.cs

@@ -69,7 +69,7 @@ namespace SafeExamBrowser.Monitoring.Keyboard
 			block |= modifier.HasFlag(KeyModifier.Alt) && key == Key.Escape && !settings.AllowAltEsc;
 			block |= modifier.HasFlag(KeyModifier.Alt) && key == Key.F4 && !settings.AllowAltF4;
 			block |= modifier.HasFlag(KeyModifier.Alt) && key == Key.Space;
-			block |= modifier.HasFlag(KeyModifier.Alt) && key == Key.Tab && !settings.AllowAltTab;
+			block |= modifier.HasFlag(KeyModifier.Alt) && key == Key.Tab;
 			block |= modifier.HasFlag(KeyModifier.Ctrl) && key == Key.Escape && !settings.AllowCtrlEsc;
 
 			if (block)

SafeExamBrowser.UserInterface.Shared/Activators/ActionCenterKeyboardActivator.cs

@@ -29,16 +29,10 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 			this.logger = logger;
 		}
 
-		public void Pause()
+		protected override void OnBeforeResume()
-		{
-			Paused = true;
-		}
-
-		public void Resume()
 		{
 			A = false;
 			LeftWindows = false;
-			Paused = false;
 		}
 
 		protected override bool Process(Key key, KeyModifier modifier, KeyState state)

SafeExamBrowser.UserInterface.Shared/Activators/ActionCenterTouchActivator.cs

@@ -31,15 +31,9 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 			this.nativeMethods = nativeMethods;
 		}
 
-		public void Pause()
+		protected override void OnBeforeResume()
-		{
-			Paused = true;
-		}
-
-		public void Resume()
 		{
 			isDown = false;
-			Paused = false;
 		}
 
 		protected override bool Process(MouseButton button, MouseButtonState state, MouseInformation info)

SafeExamBrowser.UserInterface.Shared/Activators/KeyboardActivator.cs

@@ -15,10 +15,9 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 {
 	public abstract class KeyboardActivator
 	{
-		private INativeMethods nativeMethods;
 		private Guid? hookId;
-
+		private INativeMethods nativeMethods;
-		protected bool Paused { get; set; }
+		private bool paused;
 
 		protected KeyboardActivator(INativeMethods nativeMethods)
 		{
@@ -27,6 +26,18 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 
 		protected abstract bool Process(Key key, KeyModifier modifier, KeyState state);
 
+		public void Pause()
+		{
+			OnBeforePause();
+			paused = true;
+		}
+
+		public void Resume()
+		{
+			OnBeforeResume();
+			paused = false;
+		}
+
 		public void Start()
 		{
 			hookId = nativeMethods.RegisterKeyboardHook(KeyboardHookCallback);
@@ -40,9 +51,17 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 			}
 		}
 
+		protected virtual void OnBeforePause()
+		{
+		}
+
+		protected virtual void OnBeforeResume()
+		{
+		}
+
 		private bool KeyboardHookCallback(int keyCode, KeyModifier modifier, KeyState state)
 		{
-			if (!Paused)
+			if (!paused)
 			{
 				return Process(KeyInterop.KeyFromVirtualKey(keyCode), modifier, state);
 			}

SafeExamBrowser.UserInterface.Shared/Activators/TaskViewKeyboardActivator.cs

@@ -17,7 +17,7 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 {
 	public class TaskViewKeyboardActivator : KeyboardActivator, ITaskViewActivator
 	{
-		private bool Activated, BlockActivation, LeftShift, Tab;
+		private bool Activated, LeftShift, Tab;
 		private ILogger logger;
 
 		public event ActivatorEventHandler Deactivated;
@@ -29,14 +29,22 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 			this.logger = logger;
 		}
 
-		public void Pause()
+		protected override void OnBeforePause()
 		{
-			BlockActivation = true;
+			if (Activated)
+			{
+				logger.Debug("Auto-deactivation.");
+				Deactivated?.Invoke();
+			}
+
+			Activated = false;
 		}
 
-		public void Resume()
+		protected override void OnBeforeResume()
 		{
-			BlockActivation = false;
+			Activated = false;
+			LeftShift = false;
+			Tab = false;
 		}
 
 		protected override bool Process(Key key, KeyModifier modifier, KeyState state)
@@ -73,7 +81,7 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 
 			var isActivation = Tab && changed;
 
-			if (isActivation && !BlockActivation)
+			if (isActivation)
 			{
 				Activated = true;
 

SafeExamBrowser.UserInterface.Shared/Activators/TerminationActivator.cs

@@ -27,17 +27,11 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 			this.logger = logger;
 		}
 
-		public void Pause()
+		protected override void OnBeforeResume()
-		{
-			Paused = true;
-		}
-
-		public void Resume()
 		{
 			Q = false;
 			LeftCtrl = false;
 			RightCtrl = false;
-			Paused = false;
 		}
 
 		protected override bool Process(Key key, KeyModifier modifier, KeyState state)

SafeExamBrowser.UserInterface.Shared/Activators/TouchActivator.cs

@@ -14,18 +14,29 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 {
 	public abstract class TouchActivator
 	{
-		private INativeMethods nativeMethods;
 		private Guid? hookId;
-
+		private INativeMethods nativeMethods;
-		protected bool Paused { get; set; }
+		protected bool paused;
 
 		protected TouchActivator(INativeMethods nativeMethods)
 		{
 			this.nativeMethods = nativeMethods;
 		}
 
+		protected abstract void OnBeforeResume();
 		protected abstract bool Process(MouseButton button, MouseButtonState state, MouseInformation info);
 
+		public void Pause()
+		{
+			paused = true;
+		}
+
+		public void Resume()
+		{
+			OnBeforeResume();
+			paused = false;
+		}
+
 		public void Start()
 		{
 			hookId = nativeMethods.RegisterMouseHook(MouseHookCallback);
@@ -41,7 +52,7 @@ namespace SafeExamBrowser.UserInterface.Shared.Activators
 
 		private bool MouseHookCallback(MouseButton button, MouseButtonState state, MouseInformation info)
 		{
-			if (!Paused && info.IsTouch)
+			if (!paused && info.IsTouch)
 			{
 				return Process(button, state, info);
 			}