FxCop with ColorPicker (#6464)

* fxcop fixes

* more fixes, not done yet

* supressing 1031 and ca2000 since we are expressly disposing this correctly

* catching a possible crash due to null ref if run twice

* addressing feedback

src/modules/colorPicker/ColorPickerUI/App.xaml.cs

@@ -14,11 +14,12 @@ namespace ColorPickerUI
     /// <summary>
     /// Interaction logic for App.xaml
     /// </summary>
-    public partial class App : Application
+    public partial class App : Application, IDisposable
     {
-        private Mutex _instanceMutex = null;
+        private Mutex _instanceMutex;
         private static string[] _args;
         private int _powerToysPid;
+        private bool disposedValue;
 
         [STAThread]
         public static void Main(string[] args)
@@ -27,11 +28,15 @@ namespace ColorPickerUI
             AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
             try
             {
-                var application = new App();
+                using (var application = new App())
+                {
                     application.InitializeComponent();
                     application.Run();
                 }
+            }
+#pragma warning disable CA1031 // Do not catch general exception types
             catch (Exception ex)
+#pragma warning restore CA1031 // Do not catch general exception types
             {
                 Logger.LogError("Unhandled exception", ex);
                 CursorManager.RestoreOriginalCursors();
@@ -78,5 +83,27 @@ namespace ColorPickerUI
             Logger.LogError("Unhandled exception", (e.ExceptionObject is Exception) ? (e.ExceptionObject as Exception) : new Exception());
             CursorManager.RestoreOriginalCursors();
         }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!disposedValue)
+            {
+                if (disposing)
+                {
+                    _instanceMutex?.Dispose();
+                }
+
+                // TODO: free unmanaged resources (unmanaged objects) and override finalizer
+                // TODO: set large fields to null
+                disposedValue = true;
+            }
+        }
+
+        public void Dispose()
+        {
+            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+            Dispose(disposing: true);
+            GC.SuppressFinalize(this);
+        }
     }
 }

src/modules/colorPicker/ColorPickerUI/Behaviors/GridEffectBehavior.cs

@@ -10,12 +10,11 @@ namespace ColorPicker.Behaviors
 {
     public class GridEffectBehavior : Behavior<FrameworkElement>
     {
-        private static double baseZoomImageSizeInPx = 50;
+        private static double _baseZoomImageSizeInPx = 50;
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1401:Fields should be private", Justification = "https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/dependency-property-security#:~:text=Dependency%20properties%20should%20generally%20be%20considered%20to%20be,make%20security%20guarantees%20about%20a%20dependency%20property%20value.")]
+        public static readonly DependencyProperty EffectProperty = DependencyProperty.Register("Effect", typeof(GridShaderEffect), typeof(GridEffectBehavior));
-        public static DependencyProperty EffectProperty = DependencyProperty.Register("Effect", typeof(GridShaderEffect), typeof(GridEffectBehavior));
+
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1401:Fields should be private", Justification = "https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/dependency-property-security#:~:text=Dependency%20properties%20should%20generally%20be%20considered%20to%20be,make%20security%20guarantees%20about%20a%20dependency%20property%20value.")]
+        public static readonly DependencyProperty ZoomFactorProperty = DependencyProperty.Register("ZoomFactor", typeof(double), typeof(GridEffectBehavior));
-        public static DependencyProperty ZoomFactorProperty = DependencyProperty.Register("ZoomFactor", typeof(double), typeof(GridEffectBehavior));
 
         public GridShaderEffect Effect
         {
@@ -46,11 +45,12 @@ namespace ColorPicker.Behaviors
             var relativeX = position.X / AssociatedObject.ActualWidth;
             var relativeY = position.Y / AssociatedObject.Height;
             Effect.MousePosition = new Point(relativeX, relativeY);
+
             if (ZoomFactor >= 4)
             {
                 Effect.Radius = 0.04;
                 Effect.SquareSize = ZoomFactor;
-                Effect.TextureSize = baseZoomImageSizeInPx * ZoomFactor;
+                Effect.TextureSize = _baseZoomImageSizeInPx * ZoomFactor;
             }
             else
             {

src/modules/colorPicker/ColorPickerUI/Behaviors/MoveWindowBehavior.cs

@@ -11,8 +11,7 @@ namespace ColorPicker.Behaviors
 {
     public class MoveWindowBehavior : Behavior<Window>
     {
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1401:Fields should be private", Justification = "https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/dependency-property-security#:~:text=Dependency%20properties%20should%20generally%20be%20considered%20to%20be,make%20security%20guarantees%20about%20a%20dependency%20property%20value.")]
+        public static readonly DependencyProperty LeftProperty = DependencyProperty.Register("Left", typeof(double), typeof(MoveWindowBehavior), new PropertyMetadata(new PropertyChangedCallback(LeftPropertyChanged)));
-        public static DependencyProperty LeftProperty = DependencyProperty.Register("Left", typeof(double), typeof(MoveWindowBehavior), new PropertyMetadata(new PropertyChangedCallback(LeftPropertyChanged)));
 
         private static void LeftPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
@@ -22,8 +21,7 @@ namespace ColorPicker.Behaviors
             sender.BeginAnimation(Window.LeftProperty, move, HandoffBehavior.Compose);
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1401:Fields should be private", Justification = "https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/dependency-property-security#:~:text=Dependency%20properties%20should%20generally%20be%20considered%20to%20be,make%20security%20guarantees%20about%20a%20dependency%20property%20value.")]
+        public static readonly DependencyProperty TopProperty = DependencyProperty.Register("Top", typeof(double), typeof(MoveWindowBehavior), new PropertyMetadata(new PropertyChangedCallback(TopPropertyChanged)));
-        public static DependencyProperty TopProperty = DependencyProperty.Register("Top", typeof(double), typeof(MoveWindowBehavior), new PropertyMetadata(new PropertyChangedCallback(TopPropertyChanged)));
 
         private static void TopPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {

src/modules/colorPicker/ColorPickerUI/Behaviors/ResizeBehavior.cs

@@ -11,8 +11,7 @@ namespace ColorPicker.Behaviors
 {
     public class ResizeBehavior : Behavior<FrameworkElement>
     {
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1401:Fields should be private", Justification = "https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/dependency-property-security#:~:text=Dependency%20properties%20should%20generally%20be%20considered%20to%20be,make%20security%20guarantees%20about%20a%20dependency%20property%20value.")]
+        public static readonly DependencyProperty WidthProperty = DependencyProperty.Register("Width", typeof(double), typeof(ResizeBehavior), new PropertyMetadata(new PropertyChangedCallback(WidthPropertyChanged)));
-        public static DependencyProperty WidthProperty = DependencyProperty.Register("Width", typeof(double), typeof(ResizeBehavior), new PropertyMetadata(new PropertyChangedCallback(WidthPropertyChanged)));
 
         private static void WidthPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
@@ -28,8 +27,7 @@ namespace ColorPicker.Behaviors
             sender.BeginAnimation(FrameworkElement.WidthProperty, move, HandoffBehavior.Compose);
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1401:Fields should be private", Justification = "https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/dependency-property-security#:~:text=Dependency%20properties%20should%20generally%20be%20considered%20to%20be,make%20security%20guarantees%20about%20a%20dependency%20property%20value.")]
+        public static readonly DependencyProperty HeightProperty = DependencyProperty.Register("Height", typeof(double), typeof(ResizeBehavior), new PropertyMetadata(new PropertyChangedCallback(HeightPropertyChanged)));
-        public static DependencyProperty HeightProperty = DependencyProperty.Register("Height", typeof(double), typeof(ResizeBehavior), new PropertyMetadata(new PropertyChangedCallback(HeightPropertyChanged)));
 
         private static void HeightPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {

src/modules/colorPicker/ColorPickerUI/Bootstrapper.cs

@@ -11,6 +11,7 @@ namespace ColorPicker
     {
         public static CompositionContainer Container { get; private set; }
 
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Reliability", "CA2000:Dispose objects before losing scope", Justification = "This is properly disposed of in MainWindow.Xaml.cs")]
         public static void InitializeContainer(object initPoint)
         {
             var catalog = new AssemblyCatalog(System.Reflection.Assembly.GetExecutingAssembly());

src/modules/colorPicker/ColorPickerUI/ColorPickerUI.csproj

@@ -109,6 +109,7 @@
     <Compile Include="Behaviors\GridEffectBehavior.cs" />
     <Compile Include="Helpers\IThrottledActionInvoker.cs" />
     <Compile Include="Helpers\ThrottledActionInvoker.cs" />
+    <Compile Include="NativeMethods.cs" />
     <Compile Include="Settings\IUserSettings.cs" />
     <Compile Include="Settings\SettingItem`1.cs" />
     <Compile Include="Settings\UserSettings.cs" />
@@ -117,7 +118,6 @@
     <Compile Include="Telemetry\ColorPickerCancelledEvent.cs" />
     <Compile Include="Telemetry\ColorPickerShowEvent.cs" />
     <Compile Include="Telemetry\ColorPickerZoomOpenedEvent.cs" />
-    <Compile Include="Win32Apis.cs" />
     <Compile Include="ZoomWindow.xaml.cs">
       <DependentUpon>ZoomWindow.xaml</DependentUpon>
     </Compile>
@@ -216,6 +216,11 @@
     <None Include="App.config" />
   </ItemGroup>
   <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers">
+      <Version>3.3.0</Version>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
     <PackageReference Include="System.Windows.Interactivity.WPF">
       <Version>2.0.20525</Version>
     </PackageReference>

src/modules/colorPicker/ColorPickerUI/Helpers/MonitorResolutionHelper.cs

@@ -9,7 +9,7 @@ using System.Linq;
 using System.Runtime.InteropServices;
 using System.Windows;
 using System.Windows.Media;
-using static ColorPicker.Win32Apis;
+using static ColorPicker.NativeMethods;
 
 namespace ColorPicker.Helpers
 {
@@ -17,6 +17,7 @@ namespace ColorPicker.Helpers
     {
         public static readonly HandleRef NullHandleRef = new HandleRef(null, IntPtr.Zero);
 
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "CA1801:Review unused parameters", Justification = "Interop")]
         private MonitorResolutionHelper(IntPtr monitor, IntPtr hdc)
         {
             var info = new MonitorInfoEx();
@@ -73,6 +74,7 @@ namespace ColorPicker.Helpers
 
             public ArrayList Monitors { get; private set; }
 
+            [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "CA1801:Review unused parameters", Justification = "Interop")]
             public bool Callback(
                 IntPtr monitor,
                 IntPtr hdc,

src/modules/colorPicker/ColorPickerUI/Helpers/ZoomWindowHelper.cs

@@ -28,8 +28,8 @@ namespace ColorPicker.Helpers
         private readonly AppStateHandler _appStateHandler;
         private readonly IThrottledActionInvoker _throttledActionInvoker;
 
-        private int _currentZoomLevel = 0;
+        private int _currentZoomLevel;
-        private int _previousZoomLevel = 0;
+        private int _previousZoomLevel;
 
         private ZoomWindow _zoomWindow;
 
@@ -90,7 +90,9 @@ namespace ColorPicker.Helpers
                 var x = (int)point.X - (BaseZoomImageSize / 2);
                 var y = (int)point.Y - (BaseZoomImageSize / 2);
                 var rect = new Rectangle(x, y, BaseZoomImageSize, BaseZoomImageSize);
-                var bmp = new Bitmap(rect.Width, rect.Height, PixelFormat.Format32bppArgb);
+
+                using (var bmp = new Bitmap(rect.Width, rect.Height, PixelFormat.Format32bppArgb))
+                {
                     var g = Graphics.FromImage(bmp);
                     g.CopyFromScreen(rect.Left, rect.Top, 0, 0, bmp.Size, CopyPixelOperation.SourceCopy);
 
@@ -99,6 +101,7 @@ namespace ColorPicker.Helpers
                     _zoomViewModel.ZoomArea = bitmapImage;
                     _zoomViewModel.ZoomFactor = 1;
                 }
+            }
             else
             {
                 var enlarge = (_currentZoomLevel - _previousZoomLevel) > 0 ? true : false;
@@ -110,17 +113,19 @@ namespace ColorPicker.Helpers
             ShowZoomWindow((int)point.X, (int)point.Y);
         }
 
-        private BitmapSource BitmapToImageSource(Bitmap bitmap)
+        private static BitmapSource BitmapToImageSource(Bitmap bitmap)
         {
             using (MemoryStream memory = new MemoryStream())
             {
                 bitmap.Save(memory, ImageFormat.Bmp);
                 memory.Position = 0;
+
                 BitmapImage bitmapimage = new BitmapImage();
                 bitmapimage.BeginInit();
                 bitmapimage.StreamSource = memory;
                 bitmapimage.CacheOption = BitmapCacheOption.OnLoad;
                 bitmapimage.EndInit();
+
                 return bitmapimage;
             }
         }

src/modules/colorPicker/ColorPickerUI/Keyboard/GlobalKeyboardHook.cs

@@ -6,7 +6,7 @@ using System;
 using System.ComponentModel;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
-using static ColorPicker.Win32Apis;
+using static ColorPicker.NativeMethods;
 
 namespace ColorPicker.Keyboard
 {

src/modules/colorPicker/ColorPickerUI/Keyboard/GlobalKeyboardHookEventArgs.cs

@@ -3,7 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.ComponentModel;
-using static ColorPicker.Win32Apis;
+using static ColorPicker.NativeMethods;
 
 namespace ColorPicker.Keyboard
 {

src/modules/colorPicker/ColorPickerUI/Keyboard/KeyboardMonitor.cs

@@ -11,18 +11,19 @@ using ColorPicker.Settings;
 using ColorPicker.Telemetry;
 using Microsoft.PowerToys.Settings.UI.Lib.Utilities;
 using Microsoft.PowerToys.Telemetry;
-using static ColorPicker.Win32Apis;
+using static ColorPicker.NativeMethods;
 
 namespace ColorPicker.Keyboard
 {
     [Export(typeof(KeyboardMonitor))]
-    public class KeyboardMonitor
+    public class KeyboardMonitor : IDisposable
     {
         private readonly AppStateHandler _appStateHandler;
         private readonly IUserSettings _userSettings;
 
         private List<string> _activationKeys = new List<string>();
         private GlobalKeyboardHook _keyboardHook;
+        private bool disposedValue;
 
         [ImportingConstructor]
         public KeyboardMonitor(AppStateHandler appStateHandler, IUserSettings userSettings)
@@ -135,5 +136,28 @@ namespace ColorPicker.Keyboard
                 currentlyPressedKeys.Add("Win");
             }
         }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!disposedValue)
+            {
+                if (disposing)
+                {
+                    // TODO: dispose managed state (managed objects)
+                    _keyboardHook.Dispose();
+                }
+
+                // TODO: free unmanaged resources (unmanaged objects) and override finalizer
+                // TODO: set large fields to null
+                disposedValue = true;
+            }
+        }
+
+        public void Dispose()
+        {
+            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+            Dispose(disposing: true);
+            GC.SuppressFinalize(this);
+        }
     }
 }

src/modules/colorPicker/ColorPickerUI/Mouse/CursorManager.cs

@@ -50,14 +50,16 @@ namespace ColorPicker.Mouse
                 if (curFile != null)
                 {
                     Registry.SetValue(CursorsRegistryPath, cursorRegistryName, curFile);
-                    Win32Apis.SystemParametersInfo(SPI_SETCURSORS, 0, new IntPtr(0), SPIF_SENDCHANGE);
+                    NativeMethods.SystemParametersInfo(SPI_SETCURSORS, 0, new IntPtr(0), SPIF_SENDCHANGE);
                 }
                 else
                 {
                     Logger.LogInfo("Cursor file path was null");
                 }
             }
+#pragma warning disable CA1031 // Do not catch general exception types
             catch (Exception ex)
+#pragma warning restore CA1031 // Do not catch general exception types
             {
                 Logger.LogError("Failed to change cursor", ex);
             }

src/modules/colorPicker/ColorPickerUI/Mouse/MouseHook.cs

@@ -7,7 +7,7 @@ using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Windows.Input;
 using ColorPicker.Helpers;
-using static ColorPicker.Win32Apis;
+using static ColorPicker.NativeMethods;
 
 namespace ColorPicker.Mouse
 {
@@ -21,8 +21,6 @@ namespace ColorPicker.Mouse
         private const int WM_LBUTTONDOWN = 0x0201;
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop object")]
         private const int WM_MOUSEWHEEL = 0x020A;
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop object")]
-        private const int WHEEL_DELTA = 120;
 
         private IntPtr _mouseHookHandle;
         private HookProc _mouseDelegate;

src/modules/colorPicker/ColorPickerUI/Mouse/MouseInfoProvider.cs

@@ -10,7 +10,7 @@ using System.Windows.Input;
 using System.Windows.Threading;
 using ColorPicker.Helpers;
 using ColorPicker.Settings;
-using static ColorPicker.Win32Apis;
+using static ColorPicker.NativeMethods;
 
 namespace ColorPicker.Mouse
 {
@@ -31,9 +31,13 @@ namespace ColorPicker.Mouse
             _timer.Interval = TimeSpan.FromMilliseconds(MousePullInfoIntervalInMs);
             _timer.Tick += Timer_Tick;
 
+            if (appStateMonitor != null)
+            {
                 appStateMonitor.AppShown += AppStateMonitor_AppShown;
                 appStateMonitor.AppClosed += AppStateMonitor_AppClosed;
                 appStateMonitor.AppHidden += AppStateMonitor_AppClosed;
+            }
+
             _mouseHook = new MouseHook();
             _userSettings = userSettings;
         }
@@ -79,12 +83,14 @@ namespace ColorPicker.Mouse
         private static Color GetPixelColor(System.Windows.Point mousePosition)
         {
             var rect = new Rectangle((int)mousePosition.X, (int)mousePosition.Y, 1, 1);
-            var bmp = new Bitmap(rect.Width, rect.Height, PixelFormat.Format32bppArgb);
+            using (var bmp = new Bitmap(rect.Width, rect.Height, PixelFormat.Format32bppArgb))
+            {
                 var g = Graphics.FromImage(bmp);
                 g.CopyFromScreen(rect.Left, rect.Top, 0, 0, bmp.Size, CopyPixelOperation.SourceCopy);
 
                 return bmp.GetPixel(0, 0);
             }
+        }
 
         private static System.Windows.Point GetCursorPosition()
         {

src/modules/colorPicker/ColorPickerUI/NativeMethods.cs

@@ -8,9 +8,12 @@ using System.Runtime.Versioning;
 
 namespace ColorPicker
 {
-    public static class Win32Apis
+    // https://docs.microsoft.com/en-us/visualstudio/code-quality/ca1060?view=vs-2019
+    // will have to rename
+    public static class NativeMethods
     {
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop")]
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Interop")]
         public const int WH_KEYBOARD_LL = 13;
         public const int VkSnapshot = 0x2c;
         public const int KfAltdown = 0x2000;
@@ -18,14 +21,23 @@ namespace ColorPicker
         public const int MonitorinfofPrimary = 0x00000001;
 
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop")]
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Interop")]
         public const int VK_SHIFT = 0x10;
+
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop")]
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Interop")]
         public const int VK_CONTROL = 0x11;
+
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop")]
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Interop")]
         public const int VK_MENU = 0x12;
+
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop")]
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Interop")]
         public const int VK_LWIN = 0x5B;
+
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop")]
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Interop")]
         public const int VK_RWIN = 0x5C;
 
         public delegate bool MonitorEnumProc(
@@ -114,9 +126,9 @@ namespace ColorPicker
         internal class MonitorInfoEx
         {
             public int cbSize = Marshal.SizeOf(typeof(MonitorInfoEx));
-            public Rect rcMonitor = default;
+            public Rect rcMonitor;
-            public Rect rcWork = default;
+            public Rect rcWork;
-            public int dwFlags = 0;
+            public int dwFlags;
             [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
             public char[] szDevice = new char[32];
         }

src/modules/colorPicker/ColorPickerUI/Settings/UserSettings.cs

@@ -83,7 +83,9 @@ namespace ColorPicker.Settings
                             Logger.LogError("Failed to read changed settings", ex);
                             Thread.Sleep(500);
                         }
+#pragma warning disable CA1031 // Do not catch general exception types
                         catch (Exception ex)
+#pragma warning restore CA1031 // Do not catch general exception types
                         {
                             if (retryCount > MaxNumberOfRetry)
                             {

src/modules/colorPicker/ColorPickerUI/ViewModels/MainViewModel.cs

@@ -42,11 +42,14 @@ namespace ColorPicker.ViewModels
             _appStateHandler = appStateHandler;
             _userSettings = userSettings;
 
+            if (mouseInfoProvider != null)
+            {
                 mouseInfoProvider.MouseColorChanged += Mouse_ColorChanged;
                 mouseInfoProvider.OnMouseDown += MouseInfoProvider_OnMouseDown;
                 mouseInfoProvider.OnMouseWheel += MouseInfoProvider_OnMouseWheel;
+            }
 
-            keyboardMonitor.Start();
+            keyboardMonitor?.Start();
         }
 
         public string HexColor