diff --git a/SafeExamBrowser.Runtime/App.cs b/SafeExamBrowser.Runtime/App.cs
index b1574b0d..44157a7a 100644
--- a/SafeExamBrowser.Runtime/App.cs
+++ b/SafeExamBrowser.Runtime/App.cs
@@ -17,7 +17,7 @@ namespace SafeExamBrowser.Runtime
 	public class App : Application
 	{
 		private static readonly Mutex Mutex = new Mutex(true, AppConfig.RUNTIME_MUTEX_NAME);
-		private CompositionRoot instances = new CompositionRoot();
+		private readonly CompositionRoot instances = new CompositionRoot();
 
 		[STAThread]
 		public static void Main()
diff --git a/SafeExamBrowser.Runtime/RuntimeController.cs b/SafeExamBrowser.Runtime/RuntimeController.cs
index ccdb6202..4f3c62a1 100644
--- a/SafeExamBrowser.Runtime/RuntimeController.cs
+++ b/SafeExamBrowser.Runtime/RuntimeController.cs
@@ -31,19 +31,19 @@ namespace SafeExamBrowser.Runtime
 {
 	internal class RuntimeController
 	{
-		private AppConfig appConfig;
-		private ILogger logger;
-		private IMessageBox messageBox;
-		private IOperationSequence bootstrapSequence;
-		private IRepeatableOperationSequence sessionSequence;
-		private IRuntimeHost runtimeHost;
-		private IRuntimeWindow runtimeWindow;
-		private IServiceProxy service;
-		private SessionContext sessionContext;
-		private ISplashScreen splashScreen;
-		private Action shutdown;
-		private IText text;
-		private IUserInterfaceFactory uiFactory;
+		private readonly AppConfig appConfig;
+		private readonly ILogger logger;
+		private readonly IMessageBox messageBox;
+		private readonly IOperationSequence bootstrapSequence;
+		private readonly IRepeatableOperationSequence sessionSequence;
+		private readonly IRuntimeHost runtimeHost;
+		private readonly IRuntimeWindow runtimeWindow;
+		private readonly IServiceProxy service;
+		private readonly SessionContext sessionContext;
+		private readonly ISplashScreen splashScreen;
+		private readonly Action shutdown;
+		private readonly IText text;
+		private readonly IUserInterfaceFactory uiFactory;
 
 		private SessionConfiguration Session
 		{
@@ -95,6 +95,13 @@ namespace SafeExamBrowser.Runtime
 			sessionSequence.ProgressChanged += SessionSequence_ProgressChanged;
 			sessionSequence.StatusChanged += SessionSequence_StatusChanged;
 
+			// We need to show the runtime window here already, this way implicitly setting it as the runtime application's main window.
+			// Otherwise, the splash screen is considered as the main window and thus the operating system and/or WPF does not correctly
+			// activate the runtime window once bootstrapping has finished, which in turn leads to undesired UI behavior.
+			runtimeWindow.Show();
+			runtimeWindow.BringToForeground();
+			runtimeWindow.SetIndeterminate();
+
 			splashScreen.Show();
 			splashScreen.BringToForeground();
 
diff --git a/SafeExamBrowser.UserInterface.Contracts/IProgressIndicator.cs b/SafeExamBrowser.UserInterface.Contracts/IProgressIndicator.cs
index c1ecef11..4b4a2d23 100644
--- a/SafeExamBrowser.UserInterface.Contracts/IProgressIndicator.cs
+++ b/SafeExamBrowser.UserInterface.Contracts/IProgressIndicator.cs
@@ -31,7 +31,7 @@ namespace SafeExamBrowser.UserInterface.Contracts
 		void SetIndeterminate();
 
 		/// <summary>
-		/// Sets the maximum progress value.
+		/// Sets the maximum progress value. Resets the style of the progress indicator to determinate in case it has been set to indeterminate.
 		/// </summary>
 		void SetMaxValue(int max);
 
diff --git a/SafeExamBrowser.UserInterface.Desktop/Windows/RuntimeWindow.xaml.cs b/SafeExamBrowser.UserInterface.Desktop/Windows/RuntimeWindow.xaml.cs
index fea388f6..67071d64 100644
--- a/SafeExamBrowser.UserInterface.Desktop/Windows/RuntimeWindow.xaml.cs
+++ b/SafeExamBrowser.UserInterface.Desktop/Windows/RuntimeWindow.xaml.cs
@@ -113,6 +113,7 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 
 		public void SetMaxValue(int max)
 		{
+			model.IsIndeterminate = false;
 			model.MaxProgress = max;
 		}
 
diff --git a/SafeExamBrowser.UserInterface.Desktop/Windows/SplashScreen.xaml.cs b/SafeExamBrowser.UserInterface.Desktop/Windows/SplashScreen.xaml.cs
index b0e79dc0..0074b512 100644
--- a/SafeExamBrowser.UserInterface.Desktop/Windows/SplashScreen.xaml.cs
+++ b/SafeExamBrowser.UserInterface.Desktop/Windows/SplashScreen.xaml.cs
@@ -21,7 +21,7 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 	{
 		private readonly ProgressIndicatorViewModel model;
 		private readonly IText text;
-		
+
 		private AppConfig appConfig;
 		private bool allowClose;
 
@@ -106,6 +106,7 @@ namespace SafeExamBrowser.UserInterface.Desktop.Windows
 
 		public void SetMaxValue(int max)
 		{
+			model.IsIndeterminate = false;
 			model.MaxProgress = max;
 		}
 
diff --git a/SafeExamBrowser.UserInterface.Mobile/Windows/RuntimeWindow.xaml.cs b/SafeExamBrowser.UserInterface.Mobile/Windows/RuntimeWindow.xaml.cs
index 52e25a94..57dde071 100644
--- a/SafeExamBrowser.UserInterface.Mobile/Windows/RuntimeWindow.xaml.cs
+++ b/SafeExamBrowser.UserInterface.Mobile/Windows/RuntimeWindow.xaml.cs
@@ -113,6 +113,7 @@ namespace SafeExamBrowser.UserInterface.Mobile.Windows
 
 		public void SetMaxValue(int max)
 		{
+			model.IsIndeterminate = false;
 			model.MaxProgress = max;
 		}
 
diff --git a/SafeExamBrowser.UserInterface.Mobile/Windows/SplashScreen.xaml.cs b/SafeExamBrowser.UserInterface.Mobile/Windows/SplashScreen.xaml.cs
index 4a71b802..3f9aabfe 100644
--- a/SafeExamBrowser.UserInterface.Mobile/Windows/SplashScreen.xaml.cs
+++ b/SafeExamBrowser.UserInterface.Mobile/Windows/SplashScreen.xaml.cs
@@ -106,6 +106,7 @@ namespace SafeExamBrowser.UserInterface.Mobile.Windows
 
 		public void SetMaxValue(int max)
 		{
+			model.IsIndeterminate = false;
 			model.MaxProgress = max;
 		}