Fixed cancel on exit not working

Filtration.Interface/IDocument.cs

@@ -8,7 +8,7 @@ namespace Filtration.Interface
     {
         bool IsScript { get; }
         bool IsTheme { get; }
-        Task Close();
+        Task<bool> Close();
         RelayCommand CloseCommand { get; }
     }
 }

Filtration.ThemeEditor/ViewModels/ThemeEditorViewModel.cs

@@ -186,10 +186,11 @@ namespace Filtration.ThemeEditor.ViewModels
         }
 
 #pragma warning disable 1998
-        public async Task Close()
+        public async Task<bool> Close()
 #pragma warning restore 1998
         {
            Messenger.Default.Send(new ThemeClosedMessage {ClosedViewModel = this});
+            return true;
         }
         
         private void OnAddThemeComponentCommand(ThemeComponentType themeComponentType)

Filtration/ViewModels/DesignTime/DesignTimeUpdateViewModel.cs

@@ -39,7 +39,7 @@ namespace Filtration.ViewModels.DesignTime
 
         public bool IsScript { get; }
         public bool IsTheme { get; }
-        public Task Close()
+        public Task<bool> Close()
         {
             throw new System.NotImplementedException();
         }

Filtration/ViewModels/ItemFilterScriptViewModel.cs

@@ -799,14 +799,14 @@ namespace Filtration.ViewModels
             await Close();
         }
 
-        public async Task Close()
+        public async Task<bool> Close()
         {
             if (!IsDirty)
             {
                 CloseScript();
+                return true;
             }
-            else
-            {
+
             var result = _messageBoxService.Show("Filtration",
                                                  "Save script \"" + Filename + "\"?", MessageBoxButton.YesNoCancel, MessageBoxImage.Question);
 
@@ -816,17 +816,20 @@ namespace Filtration.ViewModels
                 {
                     await SaveAsync();
                     CloseScript();
-                            break;
+                    return true;
                 }
                 case MessageBoxResult.No:
                 {
                     CloseScript();
-                            break;
+                    return true;
                 }
                 case MessageBoxResult.Cancel:
                 {
-                            return;
+                    return false;
                 }
+                default:
+                {
+                    return false;
                 }
             }
         }

Filtration/ViewModels/MainWindowViewModel.cs

@@ -768,7 +768,10 @@ namespace Filtration.ViewModels
                     continue;
                 }
 
-                await document.Close();
+                if (!await document.Close())
+                {
+                    return false;
+                }
             }
 
             return true;

Filtration/ViewModels/StartPageViewModel.cs

@@ -25,7 +25,7 @@ namespace Filtration.ViewModels
         public bool IsScript => false;
         public bool IsTheme => false;
 
-        public Task Close()
+        public Task<bool> Close()
         {
             throw new System.NotImplementedException();
         }

Filtration/ViewModels/UpdateViewModel.cs

@@ -65,9 +65,10 @@ namespace Filtration.ViewModels
 
         public bool IsInErrorState => UpdateStatus == UpdateStatus.Error;
 
-        public async Task Close()
+        public async Task<bool> Close()
         {
             await Task.FromResult(true);
+            return true;
         }
 
         public RelayCommand CloseCommand { get; }

Filtration/Views/MainWindow.xaml.cs

@@ -44,7 +44,6 @@ namespace Filtration.Views
             if (!allDocumentsClosed)
             {
                 e.Cancel = true;
-
             }
         }