From 22e4e3fa7bf4b28542d21cd6308055cc90c56e39 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Damian=20B=C3=BCchel?= <damian.buechel@let.ethz.ch>
Date: Fri, 2 Sep 2022 15:00:51 +0200
Subject: [PATCH] SEBWIN-477: Ensured multiple lock screen instructions sent by
 the server don't cause multiple lock screens.

---
 SafeExamBrowser.Client/ClientController.cs | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/SafeExamBrowser.Client/ClientController.cs b/SafeExamBrowser.Client/ClientController.cs
index c60d182a..53c04883 100644
--- a/SafeExamBrowser.Client/ClientController.cs
+++ b/SafeExamBrowser.Client/ClientController.cs
@@ -654,9 +654,18 @@ namespace SafeExamBrowser.Client
 
 		private void Server_LockScreenRequested(string message)
 		{
-			logger.Info("Received lock screen event from SEB Server.");
-			var title = text.Get(TextKey.LockScreen_Title);
-			ShowLockScreen(message, title, Enumerable.Empty<LockScreenOption>());
+			logger.Info("Attempting to show lock screen as requested by the server...");
+
+			if (!sessionLocked)
+			{
+				sessionLocked = true;
+				ShowLockScreen(message, text.Get(TextKey.LockScreen_Title), Enumerable.Empty<LockScreenOption>());
+				sessionLocked = false;
+			}
+			else
+			{
+				logger.Info("Lock screen is already active.");
+			}
 		}
 
 		private void Server_TerminationRequested()