feat: use non-blocking window messaging APIs

GlazeWM.App.Watcher/WatcherStartup.cs

@@ -93,8 +93,7 @@ private static async Task<IEnumerable<IntPtr>> GetInitialHandles(IpcClient clien
     private static void RestoreHandles(List<IntPtr> handles)
     {
       foreach (var handle in handles)
-        // TODO: Change this.
-        ShowWindow(handle, ShowWindowFlags.ShowDefault);
+        ShowWindowAsync(handle, ShowWindowFlags.ShowNoActivate);
     }
   }
 }

GlazeWM.App.WindowManager/WmStartup.cs

@@ -19,6 +19,7 @@ public sealed class WmStartup
   {
     private readonly Bus _bus;
     private readonly KeybindingService _keybindingService;
+    private readonly WindowService _windowService;
     private readonly WindowEventService _windowEventService;
     private readonly UserConfigService _userConfigService;
 
@@ -27,11 +28,13 @@ public sealed class WmStartup
     public WmStartup(
       Bus bus,
       KeybindingService keybindingService,
+      WindowService windowService,
       WindowEventService windowEventService,
       UserConfigService userConfigService)
     {
       _bus = bus;
       _keybindingService = keybindingService;
+      _windowService = windowService;
       _windowEventService = windowEventService;
       _userConfigService = userConfigService;
     }
@@ -132,9 +135,16 @@ windowAnimations is WindowAnimations.True
 
     private void OnApplicationExit()
     {
-      _bus.Invoke(new ShowAllWindowsCommand());
+      // Show all windows regardless of whether their workspace is displayed.
+      foreach (var window in _windowService.GetWindows())
+        ShowWindowAsync(window.Handle, ShowWindowFlags.ShowNoActivate);
+
+      // Clear border on the active window.
       _bus.Invoke(new SetActiveWindowBorderCommand(null));
+
+      // Destroy the system tray icon.
       _systemTrayIcon?.Remove();
+
       System.Windows.Forms.Application.Exit();
     }
   }

GlazeWM.Domain/Containers/CommandHandlers/RedrawContainersHandler.cs

@@ -46,7 +46,7 @@ public CommandResponse Handle(RedrawContainersCommand command)
 
       // Restore minimized/maximized windows. Needed to be able to move and resize them.
       foreach (var window in windowsToRestore)
-        ShowWindow(window.Handle, ShowWindowFlags.Restore);
+        ShowWindowAsync(window.Handle, ShowWindowFlags.Restore);
 
       foreach (var window in windowsToRedraw)
       {

GlazeWM.Domain/DependencyInjection.cs

@@ -70,7 +70,6 @@ public static IServiceCollection AddDomainServices(this IServiceCollection servi
       services.AddSingleton<ICommandHandler<SetMinimizedCommand>, SetMinimizedHandler>();
       services.AddSingleton<ICommandHandler<SetTilingCommand>, SetTilingHandler>();
       services.AddSingleton<ICommandHandler<SetWindowSizeCommand>, SetWindowSizeHandler>();
-      services.AddSingleton<ICommandHandler<ShowAllWindowsCommand>, ShowAllWindowsHandler>();
       services.AddSingleton<ICommandHandler<ToggleFloatingCommand>, ToggleFloatingHandler>();
       services.AddSingleton<ICommandHandler<ToggleMaximizedCommand>, ToggleMaximizedHandler>();
       services.AddSingleton<ICommandHandler<UnmanageWindowCommand>, UnmanageWindowHandler>();

GlazeWM.Domain/Windows/CommandHandlers/CloseWindowHandler.cs

@@ -11,7 +11,7 @@ public CommandResponse Handle(CloseWindowCommand command)
     {
       var windowToClose = command.WindowToClose;
 
-      SendMessage(windowToClose.Handle, SendMessageType.Close, IntPtr.Zero, IntPtr.Zero);
+      SendNotifyMessage(windowToClose.Handle, SendMessageType.Close, IntPtr.Zero, IntPtr.Zero);
 
       return CommandResponse.Ok;
     }

GlazeWM.Domain/Windows/CommandHandlers/SetMaximizedHandler.cs

@@ -10,7 +10,7 @@ public CommandResponse Handle(SetMaximizedCommand command)
     {
       var window = command.Window;
 
-      ShowWindow(window.Handle, ShowWindowFlags.Maximize);
+      ShowWindowAsync(window.Handle, ShowWindowFlags.Maximize);
 
       return CommandResponse.Ok;
     }

GlazeWM.Domain/Windows/CommandHandlers/SetMinimizedHandler.cs

@@ -10,7 +10,7 @@ public CommandResponse Handle(SetMinimizedCommand command)
     {
       var window = command.Window;
 
-      ShowWindow(window.Handle, ShowWindowFlags.Minimize);
+      ShowWindowAsync(window.Handle, ShowWindowFlags.Minimize);
 
       return CommandResponse.Ok;
     }

GlazeWM.Domain/Windows/CommandHandlers/ToggleMaximizedHandler.cs

@@ -11,9 +11,9 @@ public CommandResponse Handle(ToggleMaximizedCommand command)
       var window = command.Window;
 
       if (window.HasWindowStyle(WindowStyles.Maximize))
-        ShowWindow(window.Handle, ShowWindowFlags.Restore);
+        ShowWindowAsync(window.Handle, ShowWindowFlags.Restore);
       else
-        ShowWindow(window.Handle, ShowWindowFlags.Maximize);
+        ShowWindowAsync(window.Handle, ShowWindowFlags.Maximize);
 
       return CommandResponse.Ok;
     }

GlazeWM.Infrastructure/WindowsApi/WindowsApiService.cs

@@ -246,12 +246,13 @@ public enum ShowWindowFlags : uint
     {
       Minimize = 2,
       Maximize = 3,
-      ShowDefault = 10,
+      ShowNoActivate = 8,
       Restore = 9,
+      ShowDefault = 10,
     }
 
     [DllImport("user32.dll")]
-    public static extern bool ShowWindow(IntPtr hWnd, ShowWindowFlags flags);
+    public static extern bool ShowWindowAsync(IntPtr hWnd, ShowWindowFlags flags);
 
     [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
     public static extern int GetWindowTextLength(IntPtr hWnd);
@@ -399,7 +400,7 @@ public enum SendMessageType : uint
     }
 
     [DllImport("user32.dll", CharSet = CharSet.Auto)]
-    public static extern IntPtr SendMessage(IntPtr hWnd, SendMessageType msg, IntPtr wParam, IntPtr lParam);
+    public static extern IntPtr SendNotifyMessage(IntPtr hWnd, SendMessageType msg, IntPtr wParam, IntPtr lParam);
 
     [DllImport("user32.dll", SetLastError = true)]
     public static extern bool IsProcessDPIAware();