use mutexes

Bloxstrap/App.xaml.cs

@@ -163,19 +163,22 @@ namespace Bloxstrap
                 InstallChecker.CheckUpgrade();
 #endif
 
+            using InterProcessLock processLock = new InterProcessLock("Process", TimeSpan.FromMilliseconds(100));
+
             if (LaunchSettings.IsMenuLaunch)
             {
-                Process? menuProcess = Process.GetProcesses().Where(x => x.MainWindowTitle == $"{ProjectName} Menu").FirstOrDefault();
+                using InterProcessLock menuLock = new InterProcessLock("Menu", TimeSpan.FromMilliseconds(100));
 
-                if (menuProcess is not null)
+                if (!menuLock.IsAcquired)
                 {
-                    var handle = menuProcess.MainWindowHandle;
+                    Frontend.ShowMessageBox(
-                    Logger.WriteLine(LOG_IDENT, $"Found an already existing menu window with handle {handle}");
+                        "The Bloxstrap menu is already open.",
-                    PInvoke.SetForegroundWindow((HWND)handle);
+                        MessageBoxImage.Error
+                    );
                 }
                 else
                 {
-                    if (Process.GetProcessesByName(ProjectName).Length > 1 && !LaunchSettings.IsQuiet)
+                    if (!processLock.IsAcquired && !LaunchSettings.IsQuiet)
                         Frontend.ShowMessageBox(
                             Bloxstrap.Resources.Strings.Menu_AlreadyRunning, 
                             MessageBoxImage.Information

Bloxstrap/InterProcessLock.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Bloxstrap
+{
+    public class InterProcessLock : IDisposable
+    {
+        public Mutex Mutex { get; private set; }
+
+        public bool IsAcquired { get; private set; }
+
+        public InterProcessLock(string name, TimeSpan timeout)
+        {
+            Mutex = new Mutex(false, "Bloxstrap-" + name);
+            IsAcquired = Mutex.WaitOne(timeout);
+        }
+
+        public void Dispose()
+        {
+            if (IsAcquired)
+            {
+                Mutex.ReleaseMutex();
+                IsAcquired = false;
+            }
+        }
+    }
+}

Bloxstrap/NativeMethods.txt

@@ -1,5 +1,4 @@
-SetForegroundWindow
+FlashWindow
-FlashWindow
 GetWindowLong
 SetWindowLong
 EnumDisplaySettings