Restore SEBPatch

SafeExamBrowser.WindowsApi/Desktops/DesktopMonitor.cs

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 ETH Zürich, IT Services
+ * Copyright (c) 2025 ETH Zürich, IT Services
  *
  * 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
@@ -49,7 +49,41 @@ namespace SafeExamBrowser.WindowsApi.Desktops
 
 		private void Timer_Elapsed(object sender, ElapsedEventArgs e)
 		{
-			
+			var handle = User32.OpenInputDesktop(0, false, (uint) AccessMask.DESKTOP_NONE);
+			var name = default(string);
+			var nameLength = 0;
+
+			if (handle != IntPtr.Zero)
+			{
+				User32.GetUserObjectInformation(handle, Constant.UOI_NAME, IntPtr.Zero, 0, ref nameLength);
+
+				var namePointer = Marshal.AllocHGlobal(nameLength);
+				var success = User32.GetUserObjectInformation(handle, Constant.UOI_NAME, namePointer, nameLength, ref nameLength);
+
+				if (success)
+				{
+					name = Marshal.PtrToStringAnsi(namePointer);
+					Marshal.FreeHGlobal(namePointer);
+
+					if (name?.Equals(desktop.Name, StringComparison.OrdinalIgnoreCase) != true)
+					{
+						logger.Warn($"Detected desktop switch to '{name}' [{handle}], trying to reactivate {desktop}...");
+						desktop.Activate();
+					}
+				}
+				else
+				{
+					logger.Warn("Failed to get name of currently active desktop!");
+				}
+
+				User32.CloseDesktop(handle);
+			}
+			else
+			{
+				logger.Warn("Failed to get currently active desktop!");
+			}
+
+			timer.Start();
 		}
 	}
 }