[PT Run] Closing PT Run and new settings app when PowerToys is not running (#3853)

Closing PowerLauncher, FZ Editor and new settings app when PowerToys is not running

src/modules/fancyzones/editor/FancyZonesEditor/App.xaml.cs

@@ -2,6 +2,9 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
 using System.Windows;
 using FancyZonesEditor.Models;
 
@@ -21,6 +24,8 @@ namespace FancyZonesEditor
 
         private void OnStartup(object sender, StartupEventArgs e)
         {
+            WaitForPowerToysRunner();
+
             LayoutModel foundModel = null;
 
             foreach (LayoutModel model in ZoneSettings.DefaultModels)
@@ -57,5 +62,27 @@ namespace FancyZonesEditor
             overlay.Show();
             overlay.DataContext = foundModel;
         }
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern IntPtr OpenProcess(uint processAccess, bool bInheritHandle, int processId);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        private static extern uint WaitForSingleObject(IntPtr hHandle, uint dwMilliseconds);
+
+        private void WaitForPowerToysRunner()
+        {
+            Task.Run(() =>
+            {
+                const uint INFINITE = 0xFFFFFFFF;
+                const uint WAIT_OBJECT_0 = 0x00000000;
+                const uint SYNCHRONIZE = 0x00100000;
+
+                IntPtr powerToysProcHandle = OpenProcess(SYNCHRONIZE, false, Settings.PowerToysPID);
+                if (WaitForSingleObject(powerToysProcHandle, INFINITE) == WAIT_OBJECT_0)
+                {
+                    Environment.Exit(0);
+                }
+            });
+        }
     }
 }