diff --git a/FluentAutoClicker/App.xaml.cs b/FluentAutoClicker/App.xaml.cs
index ab9d74e..76a7709 100644
--- a/FluentAutoClicker/App.xaml.cs
+++ b/FluentAutoClicker/App.xaml.cs
@@ -27,6 +27,8 @@ namespace FluentAutoClicker;
 /// </summary>
 public partial class App : Application
 {
+    public static Window Window { get; private set; } = null!;
+
     /// <summary>
     /// Initializes the singleton application object.  This is the first line of authored code
     /// executed, and as such is the logical equivalent of main() or WinMain().
@@ -45,6 +47,4 @@ protected override void OnLaunched(Microsoft.UI.Xaml.LaunchActivatedEventArgs ar
         Window = new MainWindow();
         Window.Activate();
     }
-
-    public static Window Window { get; private set; }
 }
\ No newline at end of file
diff --git a/FluentAutoClicker/FluentAutoClicker.csproj b/FluentAutoClicker/FluentAutoClicker.csproj
index ed24f5d..0e586ee 100644
--- a/FluentAutoClicker/FluentAutoClicker.csproj
+++ b/FluentAutoClicker/FluentAutoClicker.csproj
@@ -10,6 +10,7 @@
     <RuntimeIdentifiers>win-x86;win-x64;win-arm64</RuntimeIdentifiers>
     <PublishProfile>win-$(Platform).pubxml</PublishProfile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <UseWinUI>true</UseWinUI>
     <EnableMsixTooling>true</EnableMsixTooling>
     <DefineConstants>DISABLE_XAML_GENERATED_MAIN</DefineConstants>
diff --git a/FluentAutoClicker/Helpers/AutoClicker.cs b/FluentAutoClicker/Helpers/AutoClicker.cs
index 3da99d2..0cc2be2 100644
--- a/FluentAutoClicker/Helpers/AutoClicker.cs
+++ b/FluentAutoClicker/Helpers/AutoClicker.cs
@@ -27,7 +27,7 @@ public static class AutoClicker
     [DllImport("user32.dll", SetLastError = true)]
     private static extern uint SendInput(uint nInputs, Input[] pInputs, int cbSize);
 
-    private static Thread _autoClickerThread;
+    private static Thread? _autoClickerThread;
     private static bool _isAutoClickerRunning;
 
     /// <summary>
diff --git a/FluentAutoClicker/Helpers/WindowMessageHook.cs b/FluentAutoClicker/Helpers/WindowMessageHook.cs
index ddc6ca4..5c8b075 100644
--- a/FluentAutoClicker/Helpers/WindowMessageHook.cs
+++ b/FluentAutoClicker/Helpers/WindowMessageHook.cs
@@ -29,7 +29,7 @@ public class WindowMessageHook : IEquatable<WindowMessageHook>, IDisposable
     private static readonly ConcurrentDictionary<nint, WindowMessageHook> Hooks = new();
     private static readonly Subclassproc Proc = SubclassProc;
 
-    public event EventHandler<MessageEventArgs> Message;
+    public event EventHandler<MessageEventArgs>? Message;
     private nint _hWnd;
 
     public WindowMessageHook(Window window) : this(GetHandle(window)) { }
@@ -97,7 +97,7 @@ private static nint GetHandle(Window window)
 
     private static nint SubclassProc(nint hWnd, uint uMsg, nint wParam, nint lParam, nint uIdSubclass, uint dwRefData)
     {
-        if (Hooks.TryGetValue(hWnd, out WindowMessageHook hook))
+        if (Hooks.TryGetValue(hWnd, out WindowMessageHook? hook))
         {
             MessageEventArgs e = new(hWnd, uMsg, wParam, lParam);
             hook.OnMessage(hook, e);
@@ -114,17 +114,17 @@ public override int GetHashCode()
         return _hWnd.GetHashCode();
     }
 
-    public override string ToString()
+    public override string? ToString()
     {
         return _hWnd.ToString();
     }
 
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
     {
         return Equals(obj as WindowMessageHook);
     }
 
-    public virtual bool Equals(WindowMessageHook other)
+    public virtual bool Equals(WindowMessageHook? other)
     {
         return other != null && _hWnd.Equals(other._hWnd);
     }
@@ -145,4 +145,4 @@ public MessageEventArgs(nint hWnd, uint uMsg, nint wParam, nint lParam)
     public nint WParam { get; }
     public nint LParam { get; }
     public virtual nint? Result { get; set; }
-}
\ No newline at end of file
+}
diff --git a/FluentAutoClicker/Program.cs b/FluentAutoClicker/Program.cs
index 2d9bf17..d535db8 100644
--- a/FluentAutoClicker/Program.cs
+++ b/FluentAutoClicker/Program.cs
@@ -53,7 +53,7 @@ private static bool DecideRedirection()
         bool isRedirect = false;
         AppActivationArguments args = AppInstance.GetCurrent().GetActivatedEventArgs();
         ExtendedActivationKind kind = args.Kind;
-        AppInstance keyInstance = AppInstance.FindOrRegisterForKey("MySingleInstanceApp");
+        AppInstance keyInstance = AppInstance.FindOrRegisterForKey("FluentAutoClickerApp");
 
         if (keyInstance.IsCurrent)
         {
@@ -71,7 +71,7 @@ private static bool DecideRedirection()
     [DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
     private static extern IntPtr CreateEvent(
         IntPtr lpEventAttributes, bool bManualReset,
-        bool bInitialState, string lpName);
+        bool bInitialState, string? lpName);
 
     [DllImport("kernel32.dll")]
     private static extern bool SetEvent(IntPtr hEvent);
@@ -109,7 +109,7 @@ public static void RedirectActivationTo(AppActivationArguments args,
         _ = SetForegroundWindow(process.MainWindowHandle);
     }
 
-    private static void OnActivated(object sender, AppActivationArguments args)
+    private static void OnActivated(object? sender, AppActivationArguments args)
     {
         _ = args.Kind;
     }