diff --git a/src/App.xaml.cs b/src/App.xaml.cs
index 8a26a165..69b214fa 100644
--- a/src/App.xaml.cs
+++ b/src/App.xaml.cs
@@ -323,50 +323,53 @@ private void OnNotifyIconClick(object sender, System.Windows.Forms.MouseEventArg
                         if (MainWindow.OwnedWindows.Cast<View>().Any(window => window != null && window.IsDialog))
                         {
                             MainWindow.Activate();
-                            MainWindow.Topmost = true;
-                            MainWindow.Topmost = Settings.AlwaysOnTop;
-
                             return;
                         }
 
-                        switch (MainWindow.Visibility)
+                        // Determine current window state
+                        bool isWindowVisible = MainWindow.Visibility == Visibility.Visible;
+                        bool isWindowMinimized = MainWindow.WindowState == WindowState.Minimized;
+                        bool isWindowHidden = MainWindow.Visibility == Visibility.Hidden || MainWindow.Visibility == Visibility.Collapsed;
+
+                        if (!isWindowVisible || isWindowMinimized)
                         {
-                            case Visibility.Collapsed:
-                            case Visibility.Hidden:
-                                MainWindow.Show();
+                            // Restore window properly
+                            MainWindow.ShowInTaskbar = true;
 
+                            if (isWindowMinimized)
+                            {
                                 MainWindow.WindowState = WindowState.Normal;
+                            }
+                            else if (isWindowHidden)
+                            {
+                                MainWindow.Show();
+                            }
 
-                                MainWindow.Activate();
-                                MainWindow.Focus();
+                            MainWindow.Activate();
+                            MainWindow.Focus();
 
-                                MainWindow.Topmost = true;
-                                MainWindow.Topmost = Settings.AlwaysOnTop;
-                                MainWindow.ShowInTaskbar = true;
+                            // Focus the Optimize button when restoring from notification area
+                            MainWindow.Dispatcher.BeginInvoke((Action)(() =>
+                            {
+                                var mainWindow = MainWindow as MainWindow;
 
-                                // Focus the Optimize button when restoring from notification area
-                                MainWindow.Dispatcher.BeginInvoke((Action)(() =>
+                                if (mainWindow != null)
                                 {
-                                    var mainWindow = MainWindow as MainWindow;
+                                    var optimizeButton = mainWindow.FindName("Optimize") as UIElement;
 
-                                    if (mainWindow != null)
+                                    if (optimizeButton != null)
                                     {
-                                        var optimizeButton = mainWindow.FindName("Optimize") as UIElement;
-
-                                        if (optimizeButton != null)
-                                        {
-                                            Keyboard.Focus(optimizeButton);
-                                            FocusManager.SetFocusedElement(mainWindow, optimizeButton);
-                                        }
+                                        Keyboard.Focus(optimizeButton);
+                                        FocusManager.SetFocusedElement(mainWindow, optimizeButton);
                                     }
-                                }), DispatcherPriority.ApplicationIdle);
-                                break;
-
-                            case Visibility.Visible:
-                                MainWindow.Hide();
-
-                                MainWindow.ShowInTaskbar = false;
-                                break;
+                                }
+                            }), DispatcherPriority.ApplicationIdle);
+                        }
+                        else
+                        {
+                            // Hide window
+                            MainWindow.Hide();
+                            MainWindow.ShowInTaskbar = false;
                         }
 
                         ReleaseMemory();
@@ -485,8 +488,6 @@ protected override void OnStartup(StartupEventArgs startupEvent)
                             mainWindow.Show();
                             mainWindow.Activate();
                             mainWindow.Focus();
-                            mainWindow.Topmost = true;
-                            mainWindow.Topmost = Settings.AlwaysOnTop;
                         }
 
                         // Subscribe to power events
diff --git a/src/Core/ObservableObject.cs b/src/Core/ObservableObject.cs
index bb305f0f..47724f06 100644
--- a/src/Core/ObservableObject.cs
+++ b/src/Core/ObservableObject.cs
@@ -3,6 +3,7 @@
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.CompilerServices;
+using System.Windows;
 
 namespace WinMemoryCleaner
 {
@@ -30,7 +31,20 @@ public abstract class ObservableObject : INotifyPropertyChanged
         public void RaisePropertyChanged([CallerMemberName] string propertyName = null)
         {
             if (PropertyChanged != null)
-                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
+            {
+                var handler = PropertyChanged;
+                var args = new PropertyChangedEventArgs(propertyName);
+
+                // Marshal to UI thread if necessary
+                if (Application.Current != null && Application.Current.Dispatcher != null && !Application.Current.Dispatcher.CheckAccess())
+                {
+                    Application.Current.Dispatcher.Invoke(handler, this, args);
+                }
+                else
+                {
+                    handler.Invoke(this, args);
+                }
+            }
         }
 
         /// <summary>
diff --git a/src/View/Window/MainWindow.xaml.cs b/src/View/Window/MainWindow.xaml.cs
index 24f58b93..c958c37b 100644
--- a/src/View/Window/MainWindow.xaml.cs
+++ b/src/View/Window/MainWindow.xaml.cs
@@ -5,6 +5,7 @@
 using System.Windows.Controls;
 using System.Windows.Controls.Primitives;
 using System.Windows.Input;
+using System.Windows.Threading;
 
 namespace WinMemoryCleaner
 {
@@ -213,8 +214,14 @@ private void OnOptimizeCommandCompleted()
                 }
                 else
                 {
-                    Thread.Sleep(1000);
-                    App.Shutdown();
+                    // Use DispatcherTimer to avoid blocking the UI thread
+                    var timer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(1000) };
+                    timer.Tick += (s, e) =>
+                    {
+                        timer.Stop();
+                        App.Shutdown();
+                    };
+                    timer.Start();
                 }
             }
             else