diff --git a/SpineViewer/Models/PreferenceModel.cs b/SpineViewer/Models/PreferenceModel.cs
index 4ae94d6..1575935 100644
--- a/SpineViewer/Models/PreferenceModel.cs
+++ b/SpineViewer/Models/PreferenceModel.cs
@@ -102,7 +102,7 @@ namespace SpineViewer.Models
         private bool _wallpaperView;
 
         [ObservableProperty]
-        private bool? _closeToTray = null;
+        private bool _closeToTray;
 
         [ObservableProperty]
         private bool _autoRun;
diff --git a/SpineViewer/ViewModels/MainWindow/MainWindowViewModel.cs b/SpineViewer/ViewModels/MainWindow/MainWindowViewModel.cs
index 33247c5..bdf235c 100644
--- a/SpineViewer/ViewModels/MainWindow/MainWindowViewModel.cs
+++ b/SpineViewer/ViewModels/MainWindow/MainWindowViewModel.cs
@@ -35,12 +35,12 @@ namespace SpineViewer.ViewModels.MainWindow
         public bool IsShuttingDownFromTray => _isShuttingDownFromTray;
         private bool _isShuttingDownFromTray;
 
-        public bool? CloseToTray
+        public bool CloseToTray
         {
             get => _closeToTray;
             set => SetProperty(ref _closeToTray, value);
         }
-        private bool? _closeToTray = null;
+        private bool _closeToTray;
 
         public string AutoRunWorkspaceConfigPath
         {
diff --git a/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs b/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs
index 41d42a8..5b07df6 100644
--- a/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs
+++ b/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs
@@ -295,7 +295,7 @@ namespace SpineViewer.ViewModels.MainWindow
             set => SetProperty(_vmMain.SFMLRendererViewModel.WallpaperView, value, v => _vmMain.SFMLRendererViewModel.WallpaperView = v);
         }
 
-        public bool? CloseToTray
+        public bool CloseToTray
         {
             get => _vmMain.CloseToTray;
             set => SetProperty(_vmMain.CloseToTray, value, v => _vmMain.CloseToTray = v);
diff --git a/SpineViewer/Views/MainWindow.xaml.cs b/SpineViewer/Views/MainWindow.xaml.cs
index 59fe17e..3edb6f5 100644
--- a/SpineViewer/Views/MainWindow.xaml.cs
+++ b/SpineViewer/Views/MainWindow.xaml.cs
@@ -238,11 +238,6 @@ public partial class MainWindow : Window
     {
         if (!_vm.IsShuttingDownFromTray)
         {
-            if (_vm.CloseToTray is null)
-            {
-                _vm.PreferenceViewModel.CloseToTray = MessagePopupService.YesNo(AppResource.Str_CloseToTrayQuest);
-                _vm.PreferenceViewModel.SavePreference();
-            }
             if (_vm.CloseToTray is true)
             {
                 Hide();