diff --git a/src/Stl.Fusion.Blazor/BlazorModeHelper.cs b/src/Stl.Fusion.Blazor/BlazorModeHelper.cs
index 644a2c4f1..0fed039bf 100644
--- a/src/Stl.Fusion.Blazor/BlazorModeHelper.cs
+++ b/src/Stl.Fusion.Blazor/BlazorModeHelper.cs
@@ -6,7 +6,7 @@ namespace Stl.Fusion.Blazor;
 
 public class BlazorModeHelper(NavigationManager navigator)
 {
-    public static bool IsBlazorServer { get; } = OSInfo.Kind != OSKind.WebAssembly;
+    public static readonly bool IsBlazorServer = OSInfo.Kind != OSKind.WebAssembly;
 
     protected NavigationManager Navigator { get; } = navigator;
 
diff --git a/src/Stl.Fusion.Blazor/ParameterComparison/DefaultParameterComparer.cs b/src/Stl.Fusion.Blazor/ParameterComparison/DefaultParameterComparer.cs
index 38d3bd5ca..ba38e9985 100644
--- a/src/Stl.Fusion.Blazor/ParameterComparison/DefaultParameterComparer.cs
+++ b/src/Stl.Fusion.Blazor/ParameterComparison/DefaultParameterComparer.cs
@@ -8,7 +8,7 @@ public class DefaultParameterComparer : ParameterComparer
         .GetInterfaces()
         .Single(x => Equals(x.Name, "IEventCallback"));
 
-    public static ParameterComparer Instance { get; } = new DefaultParameterComparer();
+    public static ParameterComparer Instance { get; set; } = new DefaultParameterComparer();
 
     // Mostly copied from Microsoft.AspNetCore.Components.ChangeDetection
     public override bool AreEqual(object? oldValue, object? newValue)
diff --git a/src/Stl.Fusion.EntityFramework/DbHints.cs b/src/Stl.Fusion.EntityFramework/DbHints.cs
index bf3a33595..9d42c174e 100644
--- a/src/Stl.Fusion.EntityFramework/DbHints.cs
+++ b/src/Stl.Fusion.EntityFramework/DbHints.cs
@@ -4,16 +4,16 @@ public abstract record DbHint(Symbol Value);
 
 public record DbLockingHint(Symbol Value) : DbHint(Value)
 {
-    public static DbLockingHint KeyShare { get; } = new(nameof(KeyShare));
-    public static DbLockingHint Share { get; } = new(nameof(Share));
-    public static DbLockingHint NoKeyUpdate { get; } = new(nameof(NoKeyUpdate));
-    public static DbLockingHint Update { get; } = new(nameof(Update));
+    public static readonly DbLockingHint KeyShare = new(nameof(KeyShare));
+    public static readonly DbLockingHint Share = new(nameof(Share));
+    public static readonly DbLockingHint NoKeyUpdate = new(nameof(NoKeyUpdate));
+    public static readonly DbLockingHint Update = new(nameof(Update));
 }
 
 public record DbWaitHint(Symbol Value) : DbHint(Value)
 {
-    public static DbLockingHint NoWait { get; } = new(nameof(NoWait));
-    public static DbLockingHint SkipLocked { get; } = new(nameof(SkipLocked));
+    public static readonly DbLockingHint NoWait = new(nameof(NoWait));
+    public static readonly DbLockingHint SkipLocked = new(nameof(SkipLocked));
 }
 
 public record DbCustomHint(Symbol Value) : DbHint(Value);
diff --git a/src/Stl.Fusion.Ext.Contracts/Authentication/UserIdentity.cs b/src/Stl.Fusion.Ext.Contracts/Authentication/UserIdentity.cs
index f31baded5..54ac14ada 100644
--- a/src/Stl.Fusion.Ext.Contracts/Authentication/UserIdentity.cs
+++ b/src/Stl.Fusion.Ext.Contracts/Authentication/UserIdentity.cs
@@ -8,7 +8,7 @@ namespace Stl.Fusion.Authentication;
     private static readonly ListFormat IdFormat = ListFormat.SlashSeparated;
 
     public static readonly UserIdentity None;
-    public static string DefaultSchema { get; } = "Default";
+    public static string DefaultSchema { get; set; } = "Default";
 
     [DataMember(Order = 0), MemoryPackOrder(0)]
     public Symbol Id { get; }
diff --git a/src/Stl.Fusion.Ext.Services/Extensions/KeyValueStoreExt.cs b/src/Stl.Fusion.Ext.Services/Extensions/KeyValueStoreExt.cs
index 364fcea39..41e4f799c 100644
--- a/src/Stl.Fusion.Ext.Services/Extensions/KeyValueStoreExt.cs
+++ b/src/Stl.Fusion.Ext.Services/Extensions/KeyValueStoreExt.cs
@@ -2,7 +2,7 @@ namespace Stl.Fusion.Extensions;
 
 public static class KeyValueStoreExt
 {
-    public static ListFormat ListFormat { get; } = ListFormat.SlashSeparated;
+    public static ListFormat ListFormat { get; set; } = ListFormat.SlashSeparated;
     public static char Delimiter => ListFormat.Delimiter;
 
     // Set
diff --git a/src/Stl.Fusion/Session/Session.cs b/src/Stl.Fusion/Session/Session.cs
index 813ad7b8d..eaf956a81 100644
--- a/src/Stl.Fusion/Session/Session.cs
+++ b/src/Stl.Fusion/Session/Session.cs
@@ -14,7 +14,7 @@ public sealed partial class Session : IHasId<Symbol>, IRequirementTarget,
     IEquatable<Session>, IConvertibleTo<string>, IConvertibleTo<Symbol>,
     IHasJsonCompatibleToString
 {
-    public static Session Default { get; } = new("~");
+    public static readonly Session Default = new("~");
     public static SessionFactory Factory { get; set; } = DefaultSessionFactory.New();
     public static SessionValidator Validator { get; set; } = session => !session.IsDefault();
 
diff --git a/src/Stl.Interception/ArgumentList-Generated.cs b/src/Stl.Interception/ArgumentList-Generated.cs
index 6c3d20f1a..a56ca582b 100644
--- a/src/Stl.Interception/ArgumentList-Generated.cs
+++ b/src/Stl.Interception/ArgumentList-Generated.cs
@@ -1,4 +1,4 @@
-// ReSharper disable UnusedAutoPropertyAccessor.Global
+// ReSharper disable UnusedAutoPropertyAccessor.Global
 // ReSharper disable MemberCanBePrivate.Global
 // ReSharper disable ArrangeConstructorOrDestructorBody
 using Cysharp.Text;
@@ -10,7 +10,7 @@ namespace Stl.Interception;
 
 public abstract partial record ArgumentList
 {
-    public static ImmutableArray<Type> Types { get; } = ImmutableArray.Create(new [] {
+    public static readonly ImmutableArray<Type> Types = ImmutableArray.Create(new [] {
         typeof(ArgumentList0),
         typeof(ArgumentList<>),
         typeof(ArgumentList<, >),
diff --git a/src/Stl.Interception/ArgumentList-Generated.tt b/src/Stl.Interception/ArgumentList-Generated.tt
index f99971ead..11cf8bc12 100644
--- a/src/Stl.Interception/ArgumentList-Generated.tt
+++ b/src/Stl.Interception/ArgumentList-Generated.tt
@@ -49,7 +49,7 @@ namespace Stl.Interception;
 
 public abstract partial record ArgumentList
 {
-    public static ImmutableArray<Type> Types { get; } = ImmutableArray.Create(new [] {
+    public static readonly ImmutableArray<Type> Types = ImmutableArray.Create(new [] {
         typeof(ArgumentList0),
 <# for (var itemCount = 1; itemCount <= maxItemCount; itemCount++) {
 #>
diff --git a/src/Stl.Interception/ArgumentList.cs b/src/Stl.Interception/ArgumentList.cs
index d0592d095..3f10c8858 100644
--- a/src/Stl.Interception/ArgumentList.cs
+++ b/src/Stl.Interception/ArgumentList.cs
@@ -6,7 +6,7 @@ public abstract partial record ArgumentList
 {
     protected static readonly ConcurrentDictionary<(Type, MethodInfo), Func<object, ArgumentList, object?>> InvokerCache = new();
 
-    public static ArgumentList Empty { get; } = new ArgumentList0();
+    public static readonly ArgumentList Empty = new ArgumentList0();
 
     [JsonIgnore, Newtonsoft.Json.JsonIgnore, IgnoreDataMember, MemoryPackIgnore]
     public abstract int Length { get; }
diff --git a/src/Stl.Interception/TypeViewFactory.cs b/src/Stl.Interception/TypeViewFactory.cs
index e22241840..580797c3d 100644
--- a/src/Stl.Interception/TypeViewFactory.cs
+++ b/src/Stl.Interception/TypeViewFactory.cs
@@ -9,15 +9,12 @@ TypeViewFactory<TView> For<TView>()
         where TView : class;
 }
 
-public class TypeViewFactory : ITypeViewFactory
+public class TypeViewFactory(TypeViewInterceptor interceptor) : ITypeViewFactory
 {
-    public static ITypeViewFactory Default { get; } =
+    public static ITypeViewFactory Default { get; set; } =
         new TypeViewFactory(new TypeViewInterceptor(DependencyInjection.ServiceProviderExt.Empty));
 
-    protected Interceptor Interceptor { get; }
-
-    public TypeViewFactory(TypeViewInterceptor interceptor)
-        => Interceptor = interceptor;
+    protected Interceptor Interceptor { get; } = interceptor;
 
     public object CreateView(object implementation, Type viewType)
     {
diff --git a/src/Stl.Plugins/Metadata/PluginSetInfo.cs b/src/Stl.Plugins/Metadata/PluginSetInfo.cs
index 341e09e2c..69f5020ee 100644
--- a/src/Stl.Plugins/Metadata/PluginSetInfo.cs
+++ b/src/Stl.Plugins/Metadata/PluginSetInfo.cs
@@ -2,7 +2,7 @@ namespace Stl.Plugins.Metadata;
 
 public class PluginSetInfo
 {
-    public static PluginSetInfo Empty { get; } = new(
+    public static readonly PluginSetInfo Empty = new(
         ImmutableDictionary<TypeRef, PluginInfo>.Empty,
         ImmutableDictionary<TypeRef, ImmutableHashSet<TypeRef>>.Empty,
         ImmutableDictionary<TypeRef, ImmutableArray<TypeRef>>.Empty);
@@ -81,7 +81,7 @@ public override string ToString()
 
     // Private methods
 
-    // This method is used instead of .ToHashSet to eliminate #if NETFRAMEWORK 
+    // This method is used instead of .ToHashSet to eliminate #if NETFRAMEWORK
     private static HashSet<TSource> ToHashSet<TSource>(IEnumerable<TSource> source)
         => new(source);
 
diff --git a/src/Stl.Plugins/PluginInfoProvider.cs b/src/Stl.Plugins/PluginInfoProvider.cs
index 86d5a0f2b..c42a99c44 100644
--- a/src/Stl.Plugins/PluginInfoProvider.cs
+++ b/src/Stl.Plugins/PluginInfoProvider.cs
@@ -10,7 +10,7 @@ public interface IPluginInfoProvider
     /// </summary>
     public class Query
     {
-        public static Query Instance { get; } = new();
+        public static readonly Query Instance = new();
     }
 
     ImmutableHashSet<TypeRef> GetDependencies(Type pluginType);
diff --git a/src/Stl.Rpc/WebSockets/WebSocketChannel.cs b/src/Stl.Rpc/WebSockets/WebSocketChannel.cs
index 2cad013e4..7d234dd1a 100644
--- a/src/Stl.Rpc/WebSockets/WebSocketChannel.cs
+++ b/src/Stl.Rpc/WebSockets/WebSocketChannel.cs
@@ -12,7 +12,7 @@ public sealed class WebSocketChannel<T> : Channel<T>
 {
     public record Options
     {
-        public static Options Default { get; } = new();
+        public static readonly Options Default = new();
 
         public bool OwnsWebSocket { get; init; } = true;
         public int WriteFrameSize { get; init; } = 4400;
diff --git a/src/Stl/Async/ValueTaskExt.cs b/src/Stl/Async/ValueTaskExt.cs
index a14340960..3ff613c0d 100644
--- a/src/Stl/Async/ValueTaskExt.cs
+++ b/src/Stl/Async/ValueTaskExt.cs
@@ -6,11 +6,11 @@ namespace Stl.Async;
 
 public static class ValueTaskExt
 {
-    public static ValueTask NeverEndingTask { get; } = TaskExt.NeverEndingTask.ToValueTask();
-    public static ValueTask<Unit> NeverEndingUnitTask { get; } = TaskExt.NeverEndingUnitTask.ToValueTask();
-    public static ValueTask CompletedTask { get;  } = Task.CompletedTask.ToValueTask();
-    public static ValueTask<bool> TrueTask { get;  } = FromResult(true);
-    public static ValueTask<bool> FalseTask { get;  } = FromResult(false);
+    public static readonly ValueTask NeverEndingTask = TaskExt.NeverEndingTask.ToValueTask();
+    public static readonly ValueTask<Unit> NeverEndingUnitTask = TaskExt.NeverEndingUnitTask.ToValueTask();
+    public static readonly ValueTask CompletedTask = Task.CompletedTask.ToValueTask();
+    public static readonly ValueTask<bool> TrueTask = FromResult(true);
+    public static readonly ValueTask<bool> FalseTask = FromResult(false);
 
     public static ValueTask<T> FromResult<T>(T value) => new(value);
     public static ValueTask<T> FromException<T>(Exception error) => new(Task.FromException<T>(error));
diff --git a/src/Stl/Collections/Slim/ReferenceEqualityComparer.cs b/src/Stl/Collections/Slim/ReferenceEqualityComparer.cs
index 6236e91a6..382ce49ee 100644
--- a/src/Stl/Collections/Slim/ReferenceEqualityComparer.cs
+++ b/src/Stl/Collections/Slim/ReferenceEqualityComparer.cs
@@ -3,7 +3,8 @@ namespace Stl.Collections.Slim;
 public sealed class ReferenceEqualityComparer<T> : IEqualityComparer<T>
     where T : class
 {
-    public static ReferenceEqualityComparer<T> Instance { get; } = new();
+    public static readonly ReferenceEqualityComparer<T> Instance = new();
+
     public bool Equals(T? x, T? y) => ReferenceEquals(x, y);
     public int GetHashCode(T obj) => RuntimeHelpers.GetHashCode(obj);
 }
diff --git a/src/Stl/Concurrency/GCHandlePool.cs b/src/Stl/Concurrency/GCHandlePool.cs
index c333859a5..d5c76f923 100644
--- a/src/Stl/Concurrency/GCHandlePool.cs
+++ b/src/Stl/Concurrency/GCHandlePool.cs
@@ -4,7 +4,7 @@ public sealed class GCHandlePool(GCHandlePool.Options settings) : IDisposable
 {
     public record Options
     {
-        public static Options Default { get; } = new();
+        public static readonly Options Default = new();
 
         public int Capacity { get; init; } = 1024;
         public GCHandleType HandleType { get; init; } = GCHandleType.Weak;
diff --git a/src/Stl/Conversion/Internal/CastToBaseConverter.cs b/src/Stl/Conversion/Internal/CastToBaseConverter.cs
index bdd95b1fb..d5f4a84da 100644
--- a/src/Stl/Conversion/Internal/CastToBaseConverter.cs
+++ b/src/Stl/Conversion/Internal/CastToBaseConverter.cs
@@ -3,7 +3,7 @@ namespace Stl.Conversion.Internal;
 public class CastToBaseConverter<TSource, TTarget> : Converter<TSource, TTarget>
     where TSource : TTarget
 {
-    public static CastToBaseConverter<TSource, TTarget> Instance { get; } = new();
+    public static readonly CastToBaseConverter<TSource, TTarget> Instance = new();
 
     public override TTarget Convert(TSource source)
         => source;
diff --git a/src/Stl/Conversion/Internal/CastToDescendantConverter.cs b/src/Stl/Conversion/Internal/CastToDescendantConverter.cs
index d9c318b23..dc9e4ff3d 100644
--- a/src/Stl/Conversion/Internal/CastToDescendantConverter.cs
+++ b/src/Stl/Conversion/Internal/CastToDescendantConverter.cs
@@ -3,7 +3,7 @@ namespace Stl.Conversion.Internal;
 public class CastToDescendantConverter<TSource, TTarget> : Converter<TSource, TTarget>
     where TTarget : TSource
 {
-    public static CastToDescendantConverter<TSource, TTarget> Instance { get; } = new();
+    public static readonly CastToDescendantConverter<TSource, TTarget> Instance = new();
 
     public override TTarget Convert(TSource source)
         => (TTarget) source!;
diff --git a/src/Stl/Conversion/Internal/DefaultSourceConverterProvider.cs b/src/Stl/Conversion/Internal/DefaultSourceConverterProvider.cs
index de2a35bf4..d00852c40 100644
--- a/src/Stl/Conversion/Internal/DefaultSourceConverterProvider.cs
+++ b/src/Stl/Conversion/Internal/DefaultSourceConverterProvider.cs
@@ -23,22 +23,22 @@ protected virtual Converter<TSource, TTarget> GetConverter<TTarget>()
 
         // 0. Can we simply cast to base / descendant?
         if (tTarget.IsAssignableFrom(tSource)) {
-            var pInstance =
+            var fInstance =
                 typeof(CastToBaseConverter<,>)
                     .MakeGenericType(tSource, tTarget)
-                    .GetProperty(
+                    .GetField(
                         nameof(CastToBaseConverter<TTarget, TTarget>.Instance),
                         BindingFlags.Static | BindingFlags.Public);
-            return (Converter<TSource, TTarget>) pInstance!.GetValue(null)!;
+            return (Converter<TSource, TTarget>) fInstance!.GetValue(null)!;
         }
         if (tSource.IsAssignableFrom(tTarget)) {
-            var pInstance =
+            var fInstance =
                 typeof(CastToDescendantConverter<,>)
                     .MakeGenericType(tSource, tTarget)
-                    .GetProperty(
+                    .GetField(
                         nameof(CastToDescendantConverter<TTarget, TTarget>.Instance),
                         BindingFlags.Static | BindingFlags.Public);
-            return (Converter<TSource, TTarget>) pInstance!.GetValue(null)!;
+            return (Converter<TSource, TTarget>) fInstance!.GetValue(null)!;
         }
 
         // 1. Is there IConverter<,> service?
diff --git a/src/Stl/DependencyInjection/ServiceProviderExt.cs b/src/Stl/DependencyInjection/ServiceProviderExt.cs
index 8ebd50c7f..5b2202d2f 100644
--- a/src/Stl/DependencyInjection/ServiceProviderExt.cs
+++ b/src/Stl/DependencyInjection/ServiceProviderExt.cs
@@ -2,7 +2,7 @@ namespace Stl.DependencyInjection;
 
 public static class ServiceProviderExt
 {
-    public static IServiceProvider Empty { get; } = new ServiceCollection().BuildServiceProvider();
+    public static readonly IServiceProvider Empty = new ServiceCollection().BuildServiceProvider();
 
     // Logging extensions
 
diff --git a/src/Stl/Diagnostics/ActivitySourceExt.cs b/src/Stl/Diagnostics/ActivitySourceExt.cs
index 951103f92..d3356c040 100644
--- a/src/Stl/Diagnostics/ActivitySourceExt.cs
+++ b/src/Stl/Diagnostics/ActivitySourceExt.cs
@@ -4,7 +4,7 @@ namespace Stl.Diagnostics;
 
 public static class ActivitySourceExt
 {
-    public static ActivitySource Unknown { get; } = new("<Unknown>");
+    public static readonly ActivitySource Unknown = new("<Unknown>");
 
     public static Activity? StartActivity(
         this ActivitySource activitySource,
diff --git a/src/Stl/Diagnostics/MeterExt.cs b/src/Stl/Diagnostics/MeterExt.cs
index 060f77c42..d96d46022 100644
--- a/src/Stl/Diagnostics/MeterExt.cs
+++ b/src/Stl/Diagnostics/MeterExt.cs
@@ -4,5 +4,5 @@ namespace Stl.Diagnostics;
 
 public static class MeterExt
 {
-    public static Meter Unknown { get; } = new("<Unknown>");
+    public static readonly Meter Unknown = new("<Unknown>");
 }
diff --git a/src/Stl/Diagnostics/Samplers.cs b/src/Stl/Diagnostics/Samplers.cs
index 26ade2051..b9145639e 100644
--- a/src/Stl/Diagnostics/Samplers.cs
+++ b/src/Stl/Diagnostics/Samplers.cs
@@ -10,9 +10,9 @@ public sealed record Sampler(
     Func<Sampler> Duplicate)
 {
 #pragma warning disable CS8603
-    public static Sampler Always { get; } =
+    public static readonly Sampler Always =
         new(nameof(Always), 1, static () => true, () => Always);
-    public static Sampler Never { get; } =
+    public static readonly Sampler Never =
         new(nameof(Never), 0, static () => false, () => Never);
 #pragma warning restore CS8603
 
diff --git a/src/Stl/IO/FileExt.cs b/src/Stl/IO/FileExt.cs
index e1035d450..e8bc13ffb 100644
--- a/src/Stl/IO/FileExt.cs
+++ b/src/Stl/IO/FileExt.cs
@@ -4,8 +4,8 @@ namespace Stl.IO;
 
 public static class FileExt
 {
-    public static Encoding DefaultReadEncoding { get; } = Encoding.UTF8;
-    public static Encoding DefaultWriteEncoding { get; } = new UTF8Encoding(false, true);
+    public static readonly Encoding DefaultReadEncoding = Encoding.UTF8;
+    public static readonly Encoding DefaultWriteEncoding = new UTF8Encoding(false, true);
 
     public static Task WriteText(string path, string? contents, CancellationToken cancellationToken = default)
         => WriteText(path, contents, null, cancellationToken);
diff --git a/src/Stl/Multitenancy/Tenant.cs b/src/Stl/Multitenancy/Tenant.cs
index 0bbab9471..0df0fd12d 100644
--- a/src/Stl/Multitenancy/Tenant.cs
+++ b/src/Stl/Multitenancy/Tenant.cs
@@ -3,8 +3,8 @@ namespace Stl.Multitenancy;
 [DataContract, MemoryPackable(GenerateType.VersionTolerant)]
 public partial record Tenant : IHasId<Symbol>
 {
-    public static Tenant Default { get; } = new(Symbol.Empty, "The only tenant", "");
-    public static Tenant Dummy { get; } = new("*", "Example tenant", "__example");
+    public static readonly Tenant Default = new(Symbol.Empty, "The only tenant", "");
+    public static readonly Tenant Dummy = new("*", "Example tenant", "__example");
 
     [DataMember, MemoryPackOrder(0)]
     public Symbol Id { get; init; } = Symbol.Empty;
diff --git a/src/Stl/OS/DisplayInfo.cs b/src/Stl/OS/DisplayInfo.cs
deleted file mode 100644
index d2037bfcd..000000000
--- a/src/Stl/OS/DisplayInfo.cs
+++ /dev/null
@@ -1,41 +0,0 @@
-using System.Diagnostics;
-using System.Drawing;
-using System.Globalization;
-
-namespace Stl.OS;
-
-public static class DisplayInfo
-{
-    public static Rectangle? PrimaryDisplayDimensions { get; }
-
-    static DisplayInfo()
-    {
-        PrimaryDisplayDimensions = null;
-        try {
-            switch (OSInfo.Kind) {
-            case OSKind.Windows:
-                var p = new Process() {
-                    StartInfo = new ProcessStartInfo() {
-                        FileName = "cmd.exe",
-                        Arguments = "/c wmic path Win32_VideoController get CurrentHorizontalResolution,CurrentVerticalResolution",
-                        UseShellExecute = false,
-                        RedirectStandardOutput = true,
-                        CreateNoWindow = true
-                    }
-                };
-                p.Start();
-                p.WaitForExit();
-                var wh = p.StandardOutput.ReadToEnd().TrimEnd()
-                    .Split("\r\n").Last()
-                    .Split(" ", StringSplitOptions.RemoveEmptyEntries);
-                var w = int.Parse(wh[0], NumberStyles.Integer, CultureInfo.InvariantCulture);
-                var h = int.Parse(wh[1], NumberStyles.Integer, CultureInfo.InvariantCulture);
-                PrimaryDisplayDimensions = new Rectangle(0, 0, w, h);
-                break;
-            }
-        }
-        catch {
-            PrimaryDisplayDimensions = null;
-        }
-    }
-}
diff --git a/src/Stl/OS/HardwareInfo.cs b/src/Stl/OS/HardwareInfo.cs
index a4facdd28..a617105e1 100644
--- a/src/Stl/OS/HardwareInfo.cs
+++ b/src/Stl/OS/HardwareInfo.cs
@@ -10,7 +10,7 @@ public static class HardwareInfo
         // Environment.TickCount is negative in WebAssembly @ startup
         Environment.TickCount - (RefreshIntervalTicks << 1);
 
-    public static bool IsSingleThreaded { get; } = OSInfo.IsWebAssembly;
+    public static readonly bool IsSingleThreaded = OSInfo.IsWebAssembly;
 
     public static int ProcessorCount {
         get {
diff --git a/src/Stl/Requirement.cs b/src/Stl/Requirement.cs
index 04afec1cb..857f69220 100644
--- a/src/Stl/Requirement.cs
+++ b/src/Stl/Requirement.cs
@@ -13,15 +13,15 @@ public abstract record Requirement
     public abstract object CheckUntyped([NotNull] object? value);
 #endif
 
-    public static FuncRequirement<T> New<T>(ExceptionBuilder exceptionBuilder, Func<T?, bool> validator) 
+    public static FuncRequirement<T> New<T>(ExceptionBuilder exceptionBuilder, Func<T?, bool> validator)
         => new(exceptionBuilder, validator);
-    public static FuncRequirement<T> New<T>(Func<T?, bool> validator) 
+    public static FuncRequirement<T> New<T>(Func<T?, bool> validator)
         => new(validator);
 }
 
 public abstract record Requirement<T> : Requirement
 {
-    private const string MustExistPropertyName = "MustExist";
+    private const string MustExistFieldOrPropertyName = "MustExist";
     // ReSharper disable once StaticMemberInGenericType
     private static readonly object MustExistLock = new();
     private static volatile Requirement<T>? _mustExist;
@@ -36,10 +36,10 @@ public static Requirement<T> MustExist {
 
                 var type = typeof(T);
                 var result = type
-                    .GetProperty(MustExistPropertyName, BindingFlags.Public | BindingFlags.Static)
+                    .GetField(MustExistFieldOrPropertyName, BindingFlags.Public | BindingFlags.Static)
                     ?.GetValue(null) as Requirement<T>;
                 result ??= type
-                    .GetField(MustExistPropertyName, BindingFlags.Public | BindingFlags.Static)
+                    .GetProperty(MustExistFieldOrPropertyName, BindingFlags.Public | BindingFlags.Static)
                     ?.GetValue(null) as Requirement<T>;
                 result ??= MustExistRequirement<T>.Default;
                 return _mustExist = result;
diff --git a/src/Stl/Requirements/ExceptionBuilder.cs b/src/Stl/Requirements/ExceptionBuilder.cs
index 293b307d4..a66783636 100644
--- a/src/Stl/Requirements/ExceptionBuilder.cs
+++ b/src/Stl/Requirements/ExceptionBuilder.cs
@@ -5,8 +5,10 @@ namespace Stl.Requirements;
 
 public readonly record struct ExceptionBuilder
 {
-    public static Func<string, Exception> DefaultExceptionFactory { get; } = message => new ValidationException(message);
-    public static string DefaultMessageTemplate { get; } = "{0}: validation failed.";
+    public static Func<string, Exception> DefaultExceptionFactory { get; set; }
+        = message => new ValidationException(message);
+    public static string DefaultMessageTemplate { get; set; }
+        = "{0}: validation failed.";
 
     public string? MessageTemplate { get; init; }
     public string? TargetName { get; init; }
@@ -41,7 +43,7 @@ public Exception Build<TValue>(TValue? value)
                 string.Format(CultureInfo.InvariantCulture, message, targetName, value)),
             Func<Exception> simple => simple.Invoke(),
             _ => DefaultExceptionFactory.Invoke(
-                string.Format(CultureInfo.InvariantCulture, message, targetName, value)), 
+                string.Format(CultureInfo.InvariantCulture, message, targetName, value)),
         };
         return exception;
     }
diff --git a/src/Stl/Requirements/MustExistRequirement.cs b/src/Stl/Requirements/MustExistRequirement.cs
index 6682bc2bc..cf8bad0eb 100644
--- a/src/Stl/Requirements/MustExistRequirement.cs
+++ b/src/Stl/Requirements/MustExistRequirement.cs
@@ -5,7 +5,7 @@ namespace Stl.Requirements;
 
 public record MustExistRequirement<T> : CustomizableRequirementBase<T>
 {
-    public static MustExistRequirement<T> Default { get; } = new();
+    public static readonly MustExistRequirement<T> Default = new();
 
     public MustExistRequirement()
         => ExceptionBuilder = new("'{0}' is not found.", message => new ValidationException(message));
diff --git a/src/Stl/Requirements/ServiceExceptionWrapper.cs b/src/Stl/Requirements/ServiceExceptionWrapper.cs
index 7c738f500..d1438bd20 100644
--- a/src/Stl/Requirements/ServiceExceptionWrapper.cs
+++ b/src/Stl/Requirements/ServiceExceptionWrapper.cs
@@ -4,7 +4,7 @@ namespace Stl.Requirements;
 
 public record ServiceExceptionWrapper<T>(Requirement<T> BaseRequirement) : Requirement<T>
 {
-    public static ServiceExceptionWrapper<T> Default { get; } =
+    public static readonly ServiceExceptionWrapper<T> Default =
         new(MustExistRequirement<T>.Default);
 
     public override bool IsSatisfied(T? value)
diff --git a/src/Stl/Serialization/ByteSerializer.cs b/src/Stl/Serialization/ByteSerializer.cs
index 9688cfe17..55f6b022c 100644
--- a/src/Stl/Serialization/ByteSerializer.cs
+++ b/src/Stl/Serialization/ByteSerializer.cs
@@ -20,7 +20,7 @@ public static IByteSerializer NewAsymmetric(IByteSerializer reader, IByteSeriali
 
 public static class ByteSerializer<T>
 {
-    public static IByteSerializer<T> Default { get; } = ByteSerializer.Default.ToTyped<T>();
+    public static readonly IByteSerializer<T> Default = ByteSerializer.Default.ToTyped<T>();
     public static readonly IByteSerializer<T> None = NoneByteSerializer<T>.Instance;
     public static readonly IByteSerializer<T> Null = NullByteSerializer<T>.Instance;
 
diff --git a/src/Stl/Serialization/Internal/NoneByteSerializer.cs b/src/Stl/Serialization/Internal/NoneByteSerializer.cs
index 5fed4f40c..37775185f 100644
--- a/src/Stl/Serialization/Internal/NoneByteSerializer.cs
+++ b/src/Stl/Serialization/Internal/NoneByteSerializer.cs
@@ -7,7 +7,7 @@ namespace Stl.Serialization.Internal;
 /// </summary>
 public sealed class NoneByteSerializer : IByteSerializer
 {
-    public static NoneByteSerializer Instance { get; } = new();
+    public static readonly NoneByteSerializer Instance = new();
 
     public object? Read(ReadOnlyMemory<byte> data, Type type, out int readLength)
         => throw Errors.NoSerializer();
@@ -24,7 +24,7 @@ public IByteSerializer<T> ToTyped<T>(Type? serializedType = null)
 /// </summary>
 public sealed class NoneByteSerializer<T> : IByteSerializer<T>
 {
-    public static NoneByteSerializer<T> Instance { get; } = new();
+    public static readonly NoneByteSerializer<T> Instance = new();
 
     public T Read(ReadOnlyMemory<byte> data, out int readLength)
         => throw Errors.NoSerializer();
diff --git a/src/Stl/Serialization/Internal/NoneTextSerializer.cs b/src/Stl/Serialization/Internal/NoneTextSerializer.cs
index f9e8aa392..adf56f3fd 100644
--- a/src/Stl/Serialization/Internal/NoneTextSerializer.cs
+++ b/src/Stl/Serialization/Internal/NoneTextSerializer.cs
@@ -7,7 +7,7 @@ namespace Stl.Serialization.Internal;
 /// </summary>
 public sealed class NoneTextSerializer : ITextSerializer
 {
-    public static NoneTextSerializer Instance { get; } = new();
+    public static readonly NoneTextSerializer Instance = new();
 
     public bool PreferStringApi => false;
 
@@ -36,7 +36,7 @@ public ITextSerializer<T> ToTyped<T>(Type? serializedType = null)
 /// </summary>
 public sealed class NoneTextSerializer<T> : ITextSerializer<T>
 {
-    public static NoneTextSerializer<T> Instance { get; } = new();
+    public static readonly NoneTextSerializer<T> Instance = new();
 
     public bool PreferStringApi => false;
 
diff --git a/src/Stl/Serialization/Internal/NullByteSerializer.cs b/src/Stl/Serialization/Internal/NullByteSerializer.cs
index 1b78679ab..62005b4bd 100644
--- a/src/Stl/Serialization/Internal/NullByteSerializer.cs
+++ b/src/Stl/Serialization/Internal/NullByteSerializer.cs
@@ -7,7 +7,7 @@ namespace Stl.Serialization.Internal;
 /// </summary>
 public sealed class NullByteSerializer : IByteSerializer
 {
-    public static NullByteSerializer Instance { get; } = new();
+    public static readonly NullByteSerializer Instance = new();
 
     public object? Read(ReadOnlyMemory<byte> data, Type type, out int readLength)
     {
@@ -27,7 +27,7 @@ public IByteSerializer<T> ToTyped<T>(Type? serializedType = null)
 /// </summary>
 public sealed class NullByteSerializer<T> : IByteSerializer<T>
 {
-    public static NullByteSerializer<T> Instance { get; } = new();
+    public static readonly NullByteSerializer<T> Instance = new();
 
     public T Read(ReadOnlyMemory<byte> data, out int readLength)
     {
diff --git a/src/Stl/Serialization/Internal/NullTextSerializer.cs b/src/Stl/Serialization/Internal/NullTextSerializer.cs
index 9f9af6b33..15b1ff684 100644
--- a/src/Stl/Serialization/Internal/NullTextSerializer.cs
+++ b/src/Stl/Serialization/Internal/NullTextSerializer.cs
@@ -7,7 +7,7 @@ namespace Stl.Serialization.Internal;
 /// </summary>
 public sealed class NullTextSerializer : ITextSerializer
 {
-    public static NullTextSerializer Instance { get; } = new();
+    public static readonly NullTextSerializer Instance = new();
 
     public bool PreferStringApi => false;
 
@@ -50,7 +50,7 @@ public ITextSerializer<T> ToTyped<T>(Type? serializedType = null)
 /// </summary>
 public sealed class NullTextSerializer<T> : ITextSerializer<T>
 {
-    public static NullTextSerializer<T> Instance { get; } = new();
+    public static readonly NullTextSerializer<T> Instance = new();
 
     public bool PreferStringApi => false;
 
diff --git a/src/Stl/Serialization/TextSerializer.cs b/src/Stl/Serialization/TextSerializer.cs
index d69544e92..0e96e259e 100644
--- a/src/Stl/Serialization/TextSerializer.cs
+++ b/src/Stl/Serialization/TextSerializer.cs
@@ -14,7 +14,7 @@ public static ITextSerializer NewAsymmetric(ITextSerializer reader, ITextSeriali
 
 public static class TextSerializer<T>
 {
-    public static ITextSerializer<T> Default { get; } = TextSerializer.Default.ToTyped<T>();
+    public static readonly ITextSerializer<T> Default = TextSerializer.Default.ToTyped<T>();
     public static readonly ITextSerializer<T> None = NoneTextSerializer<T>.Instance;
     public static readonly ITextSerializer<T> Null  = NullTextSerializer<T>.Instance;
 
diff --git a/src/Stl/Time/TimerSet.cs b/src/Stl/Time/TimerSet.cs
index 53e9341ef..c29a3403f 100644
--- a/src/Stl/Time/TimerSet.cs
+++ b/src/Stl/Time/TimerSet.cs
@@ -3,9 +3,7 @@ namespace Stl.Time;
 public record TimerSetOptions
 {
     public static readonly TimerSetOptions Default = new();
-
-    // ReSharper disable once StaticMemberInGenericType
-    public static TimeSpan MinQuanta { get; } = TimeSpan.FromMilliseconds(10);
+    public static readonly TimeSpan MinQuanta = TimeSpan.FromMilliseconds(10);
 
     public TimeSpan Quanta { get; init; } = TimeSpan.FromSeconds(1);
     public IMomentClock Clock { get; init; } = MomentClockSet.Default.CpuClock;
diff --git a/tests/Stl.Fusion.Tests/Services/DisplayInfo.cs b/tests/Stl.Fusion.Tests/Services/DisplayInfo.cs
new file mode 100644
index 000000000..b38b820ad
--- /dev/null
+++ b/tests/Stl.Fusion.Tests/Services/DisplayInfo.cs
@@ -0,0 +1,41 @@
+using System.Drawing;
+using System.Globalization;
+using Stl.OS;
+
+namespace Stl.Fusion.Tests.Services;
+
+public static class DisplayInfo
+{
+    public static readonly Rectangle? PrimaryDisplayDimensions;
+
+    static DisplayInfo()
+    {
+        PrimaryDisplayDimensions = null;
+        try {
+            switch (OSInfo.Kind) {
+                case OSKind.Windows:
+                    var p = new Process() {
+                        StartInfo = new ProcessStartInfo() {
+                            FileName = "cmd.exe",
+                            Arguments = "/c wmic path Win32_VideoController get CurrentHorizontalResolution,CurrentVerticalResolution",
+                            UseShellExecute = false,
+                            RedirectStandardOutput = true,
+                            CreateNoWindow = true
+                        }
+                    };
+                    p.Start();
+                    p.WaitForExit();
+                    var wh = p.StandardOutput.ReadToEnd().TrimEnd()
+                        .Split("\r\n").Last()
+                        .Split(" ", StringSplitOptions.RemoveEmptyEntries);
+                    var w = int.Parse(wh[0], NumberStyles.Integer, CultureInfo.InvariantCulture);
+                    var h = int.Parse(wh[1], NumberStyles.Integer, CultureInfo.InvariantCulture);
+                    PrimaryDisplayDimensions = new Rectangle(0, 0, w, h);
+                    break;
+            }
+        }
+        catch {
+            PrimaryDisplayDimensions = null;
+        }
+    }
+}
diff --git a/tests/Stl.Fusion.Tests/Services/ScreenshotService.cs b/tests/Stl.Fusion.Tests/Services/ScreenshotService.cs
index d73402c2a..4c190e304 100644
--- a/tests/Stl.Fusion.Tests/Services/ScreenshotService.cs
+++ b/tests/Stl.Fusion.Tests/Services/ScreenshotService.cs
@@ -1,7 +1,6 @@
 using System.Drawing;
 using System.Drawing.Drawing2D;
 using System.Drawing.Imaging;
-using Stl.OS;
 
 namespace Stl.Fusion.Tests.Services;
 
diff --git a/tests/Stl.Tests/CommandR/Services/Commands.cs b/tests/Stl.Tests/CommandR/Services/Commands.cs
index 2e971db8b..98c02d129 100644
--- a/tests/Stl.Tests/CommandR/Services/Commands.cs
+++ b/tests/Stl.Tests/CommandR/Services/Commands.cs
@@ -19,7 +19,7 @@ public record DivCommand : ICommand<double>
 
 public record RecSumCommand : ICommand<double>
 {
-    public static AsyncLocal<object> Tag { get; } = new();
+    public static readonly AsyncLocal<object> Tag = new();
 
     public double[] Arguments { get; init; } = Array.Empty<double>();
 }