diff --git a/contrib/bruno/opencollection.yml b/contrib/bruno/opencollection.yml
index f072bf40..1d584584 100644
--- a/contrib/bruno/opencollection.yml
+++ b/contrib/bruno/opencollection.yml
@@ -20,7 +20,6 @@ request:
     flow: authorization_code
     authorizationUrl: "{{Authority}}/connect/authorize"
     accessTokenUrl: "{{Authority}}/connect/token"
-    refreshTokenUrl: https://yavsc.pschneider.fr/connect/token
     callbackUrl: "{{Authority}}"
     credentials:
       clientId: postit
diff --git a/src/PostIt/PostIt/App.axaml.cs b/src/PostIt/PostIt/App.axaml.cs
index 84312064..b474b37b 100644
--- a/src/PostIt/PostIt/App.axaml.cs
+++ b/src/PostIt/PostIt/App.axaml.cs
@@ -69,6 +69,7 @@ public partial class App : Application
         services.AddSingleton(api);
         services.AddSingleton(client);
         services.AddTransient<MainPageViewModel>();
+        services.AddTransient<Settings>();
         services.AddTransient<HomePageViewModel>();
         services.AddTransient<SignaturePageViewModel>();
 
diff --git a/src/PostIt/PostIt/Settings/AuthenticationSettings.cs b/src/PostIt/PostIt/Settings/AuthenticationSettings.cs
index ad71063b..9ece1e45 100644
--- a/src/PostIt/PostIt/Settings/AuthenticationSettings.cs
+++ b/src/PostIt/PostIt/Settings/AuthenticationSettings.cs
@@ -1,6 +1,5 @@
 using CommunityToolkit.Mvvm.ComponentModel;
 using System;
-using System.Text.Json.Serialization;
 
 public partial class AuthenticationSettings : ObservableObject
 {
@@ -41,82 +40,4 @@ public partial class AuthenticationSettings : ObservableObject
     [ObservableProperty]
     public partial string RedirectUri { get; set; } = DefaultDesktopRedirectUri;
 
-    /// <summary>
-    /// Space-separated view of <see cref="Scopes"/>. Exists for the
-    /// <c>SettingsPage</c> TextBox binding — a <c>string[]</c> does not
-    /// round-trip through XAML binding to <c>TextBox.Text</c>, so we
-    /// expose the array as a string here and re-parse on assignment.
-    /// <para>
-    /// <c>[JsonIgnore]</c> on purpose: <see cref="Scopes"/> is the
-    /// persisted shape (matches the on-disk format in
-    /// <c>postit-settings.json</c> and the runtime contract in
-    /// <see cref="PostIt.ViewModels.Settings.GetOidcClientOptions"/>).
-    /// Writing this property back to disk would duplicate the
-    /// information and confuse the deserializer.
-    /// </para>
-    /// </summary>
-    [JsonIgnore]
-    [ObservableProperty]
-    public partial string ScopeListText { get; set; } = string.Empty;
-
-    /// <summary>
-    /// Refresh <see cref="ScopeListText"/> from <see cref="Scopes"/> so
-    /// the TextBox shows the current persisted state after a Load().
-    /// Called from <c>Settings.ApplyJson</c> on each disk / embedded
-    /// hydration; the source generator's <c>OnScopesChanged</c> partial
-    /// below keeps the two in sync in the other direction (edits made
-    /// in the TextBox).
-    /// </summary>
-    public void RefreshScopeListText()
-    {
-        ScopeListText = Scopes is null ? string.Empty : string.Join(' ', Scopes);
-    }
-
-    partial void OnScopeListTextChanged(string value)
-    {
-        if (Scopes is null)
-        {
-            Scopes = Array.Empty<string>();
-        }
-        // Split on any whitespace, drop empties. Matches what
-        // string.Join(' ', Scopes) produces when Scopes is null-free,
-        // so a round-trip (Display → Edit → Display) is lossless
-        // for sane inputs.
-        var parts = value?.Split(
-            new[] { ' ', '\t', '\n', '\r' },
-            StringSplitOptions.RemoveEmptyEntries) ?? Array.Empty<string>();
-
-        // Skip the write if the parsed array is equal to the current
-        // one — avoids a PropertyChanged loop between OnScopesChanged
-        // and OnScopeListTextChanged when RefreshScopeListText runs.
-        if (Scopes is not null && Scopes.Length == parts.Length)
-        {
-            var same = true;
-            for (var i = 0; i < parts.Length; i++)
-            {
-                if (!string.Equals(Scopes[i], parts[i], StringComparison.Ordinal))
-                {
-                    same = false;
-                    break;
-                }
-            }
-            if (same) return;
-        }
-        Scopes = parts;
-    }
-
-    partial void OnScopesChanged(string[] value)
-    {
-        // Keep ScopeListText in sync when Scopes is reassigned from
-        // outside (JSON hydration, MergeScopes, programmatic
-        // updates). Compute the new value and only fire if it
-        // differs from what's already shown, otherwise the TextBox
-        // would briefly flicker / re-set the caret on every load.
-        var newText = value is null ? string.Empty : string.Join(' ', value);
-        if (!string.Equals(ScopeListText, newText, StringComparison.Ordinal))
-        {
-            ScopeListText = newText;
-        }
-    }
-
 }
diff --git a/src/PostIt/PostIt/ViewModels/Settings.cs b/src/PostIt/PostIt/ViewModels/Settings.cs
index 5bd3a844..98085f0c 100644
--- a/src/PostIt/PostIt/ViewModels/Settings.cs
+++ b/src/PostIt/PostIt/ViewModels/Settings.cs
@@ -361,15 +361,6 @@ public partial class Settings : ViewModelBase
             // triggered by the assignments above doesn't leave it
             // stuck at true.
             IsDirty = false;
-            // Refresh the space-separated ScopeListText view after
-            // hydration so the SettingsPage TextBox reflects the
-            // loaded scopes (and not the default empty string the
-            // ObservableProperty was constructed with). OnScopesChanged
-            // already tries to do this, but it skips when the new
-            // array parses to the same text — calling explicitly
-            // forces a re-sync and normalises any whitespace the
-            // JSON might have introduced.
-            this.Authentication?.RefreshScopeListText();
             // Re-notify the command in case the button was bound
             // before Load finished and the CanExecute cache is
             // stale.
diff --git a/src/PostIt/PostIt/Views/SettingsPage.axaml b/src/PostIt/PostIt/Views/SettingsPage.axaml
index 96f563a7..aeba19f0 100644
--- a/src/PostIt/PostIt/Views/SettingsPage.axaml
+++ b/src/PostIt/PostIt/Views/SettingsPage.axaml
@@ -5,7 +5,8 @@
         x:Class="PostIt.Views.SettingsPage"
         xmlns:vm="using:PostIt.ViewModels"
         x:DataType="vm:Settings"
-      >
+        Width="400"
+        Height="300">
     <Grid>
         <Grid.RowDefinitions>
             <RowDefinition Height="Auto"/>
@@ -19,8 +20,6 @@
             <RowDefinition Height="Auto"/>
             <RowDefinition Height="Auto"/>
             <RowDefinition Height="Auto"/>
-            <RowDefinition Height="Auto"/>
-            <RowDefinition Height="Auto"/>
         </Grid.RowDefinitions>
 
         <TextBlock Grid.Row="0" Text="Authority"/>
@@ -31,33 +30,25 @@
         <TextBox Grid.Row="3" x:Name="ClientIdTextBox"
         Text="{Binding Authentication.ClientId, Mode=TwoWay}"/>
 
-        <TextBlock Grid.Row="4" Text="Scopes (space-separated)"/>
-        <TextBox Grid.Row="5" x:Name="ScopesTextBox"
-        Text="{Binding Authentication.ScopeListText, Mode=TwoWay}"/>
-
-        <TextBlock Grid.Row="6" Text="Blogs API URL"/>
-        <TextBox Grid.Row="7" x:Name="BlogsApiUrlTextBox"
+        <TextBlock Grid.Row="4" Text="Blogs API URL"/>
+        <TextBox Grid.Row="5" x:Name="BlogsApiUrlTextBox"
         Text="{Binding BlogsApiUrl, Mode=TwoWay}"/>
 
-        <TextBlock Grid.Row="8" Text="Business API URL"/>
-        <TextBox Grid.Row="9" x:Name="BusinessApiUrlTextBox"
+        <TextBlock Grid.Row="6" Text="Business API URL"/>
+        <TextBox Grid.Row="7" x:Name="BusinessApiUrlTextBox"
         Text="{Binding BusinessApiUrl, Mode=TwoWay}"/>
 
-        <TextBlock Grid.Row="10" Text="Dark mode"/>
-        <CheckBox Grid.Row="11" x:Name="DarkModeCheckBox" IsChecked="{Binding DarkMode, Mode=TwoWay}"/>
+        <TextBlock Grid.Row="8" Text="Dark mode"/>
+        <CheckBox Grid.Row="9" x:Name="DarkModeCheckBox" IsChecked="{Binding DarkMode, Mode=TwoWay}"/>
 
-        <!-- Sauver: bound to the Save RelayCommand on the Settings
-             VM. The source generator emits an ICommand property whose
-             name matches the source method exactly (no "Command"
-             suffix is added), so we bind {Binding Save} here. See
-             AGENTS.md "Avalonia + CommunityToolkit.Mvvm : conventions
-             de binding pour [RelayCommand]" for the full rationale.
-             IsEnabled tracks IsDirty so the button auto-disables
-             when there's nothing to persist. -->
-        <Button Grid.Row="12" Content="Sauver"
+        <!-- Sauver: bound to the SaveCommand on the Settings VM, with
+             IsEnabled driven by the inverse of IsDirty so the button
+             auto-disables when there's nothing to persist. -->
+        <Button Grid.Row="10" Content="Sauver"
                 HorizontalAlignment="Right"
-                Command="{Binding Save}"
-                IsEnabled="{Binding IsDirty}"/>
+                Margin="0,12,0,0"
+                Command="{Binding SaveCommand}"
+                IsEnabled="{Binding !IsDirty}"/>
 
     </Grid>
 </ContentPage>
diff --git a/src/Yavsc.Org.Tests/ComputeKidTests.cs b/src/Yavsc.Org.Tests/ComputeKidTests.cs
deleted file mode 100644
index af9d94a9..00000000
--- a/src/Yavsc.Org.Tests/ComputeKidTests.cs
+++ /dev/null
@@ -1,165 +0,0 @@
-using System;
-using System.IO;
-using System.Linq;
-using System.Security.Cryptography;
-using System.Security.Cryptography.X509Certificates;
-using Xunit;
-using Yavsc.Extensions;
-
-namespace Yavsc.Org.Tests;
-
-/// <summary>
-/// Tests for <see cref="HostingExtensions.ComputeKid"/>, the
-/// helper that derives the JWT <c>kid</c> header / JWKS key id
-/// from the signing certificate. The kid is consumed by every
-/// resource server (Yavsc.Blogs, Yavsc.Api) to match a token to
-/// the right key in the JWKS, so getting its shape and stability
-/// right is the whole point of the fix in commit 2c6d1157
-/// (IDX10500 regression).
-/// </summary>
-/// <remarks>
-/// We don't load the production cert (Let's Encrypt PEM + RSA
-/// private key) — we generate throwaway self-signed certs in a
-/// temp dir. The contract under test is the truncation /
-/// encoding of the thumbprint, which is independent of the key
-/// type and the cert issuer.
-/// </remarks>
-public class ComputeKidTests : IDisposable
-{
-    private readonly string _tempDir;
-
-    public ComputeKidTests()
-    {
-        _tempDir = Path.Combine(
-            Path.GetTempPath(),
-            "yavsc-compute-kid-tests-" + Guid.NewGuid().ToString("N"));
-        Directory.CreateDirectory(_tempDir);
-    }
-
-    public void Dispose()
-    {
-        try { Directory.Delete(_tempDir, recursive: true); }
-        catch { /* best effort — Temp gets cleaned eventually */ }
-    }
-
-    [Fact]
-    public void ComputeKid_returns_first_16_hex_chars_of_cert_thumbprint()
-    {
-        var certPath = WriteSelfSignedCertRsa(out var expectedThumbHex);
-
-        var kid = HostingExtensions.ComputeKid(certPath);
-
-        // 16 hex chars = 64 bits, enough to be globally unique
-        // within a deployment and compact enough for a JWT header.
-        Assert.Equal(16, kid.Length);
-        Assert.True(
-            kid.All(c => "0123456789ABCDEF".Contains(c)),
-            $"kid '{kid}' contains non-uppercase-hex characters");
-
-        // Match the first 16 chars of the thumbprint exactly. We
-        // compute the expected value from the same cert the helper
-        // was given — no magic constants, no copy-paste of the
-        // truncation logic under test.
-        Assert.Equal(expectedThumbHex[..16], kid);
-    }
-
-    [Fact]
-    public void ComputeKid_is_stable_across_repeated_reads()
-    {
-        var certPath = WriteSelfSignedCertRsa(out _);
-
-        var first = HostingExtensions.ComputeKid(certPath);
-        var second = HostingExtensions.ComputeKid(certPath);
-        var third = HostingExtensions.ComputeKid(certPath);
-
-        // Stability matters: a non-deterministic kid would
-        // invalidate tokens on every IdentityServer restart.
-        Assert.Equal(first, second);
-        Assert.Equal(second, third);
-    }
-
-    [Fact]
-    public void ComputeKid_differs_between_distinct_certificates()
-    {
-        var certPathA = WriteSelfSignedCertRsa(out _);
-        var certPathB = WriteSelfSignedCertRsa(out _);
-
-        var kidA = HostingExtensions.ComputeKid(certPathA);
-        var kidB = HostingExtensions.ComputeKid(certPathB);
-
-        // Two independent RNG-drawn RSA keys will (in practice
-        // always) yield different thumbprints. A 64-bit truncated
-        // space has collisions at ~2^32 certs; we won't get there.
-        Assert.NotEqual(kidA, kidB);
-    }
-
-    [Fact]
-    public void ComputeKid_uses_thumbprint_not_subject_or_serial()
-    {
-        // The previous fix-message claimed SHA-256; the helper
-        // actually reads X509Certificate2.GetCertHash() which is
-        // SHA-1. Pin that behaviour so a future refactor that
-        // switches to SHA-256 (or any other digest) is forced to
-        // update the test deliberately.
-        var certPath = WriteSelfSignedCertRsa(out var thumbHex);
-
-        var kid = HostingExtensions.ComputeKid(certPath);
-
-        // 16 hex chars is half of a 20-byte SHA-1 thumbprint.
-        // SHA-256 would be 32 bytes (64 hex chars) before
-        // truncation; SHA-1 is the only common digest whose
-        // hex encoding fits the 16-char prefix we observe.
-        Assert.Equal(20, thumbHex.Length / 2);
-        Assert.Equal(thumbHex[..16], kid);
-    }
-
-    [Fact]
-    public void ComputeKid_propagates_cryptographic_exception_for_missing_file()
-    {
-        // The wrapper LoadSigningCredentials wraps this in an
-        // InvalidOperationException, but ComputeKid itself is a
-        // plain helper — it must surface the parser error so the
-        // wrapper can attach the cert path to the message. We
-        // assert against the base CryptographicException rather
-        // than the concrete subtype because the runtime picks
-        // different leaf types per platform (on Linux/OpenSSL we
-        // get Interop+Crypto+OpenSslCryptographicException, on
-        // Windows we'd get the older CryptographicException
-        // directly); the contract is the same either way.
-        var missing = Path.Combine(_tempDir, "does-not-exist.pem");
-
-        Assert.ThrowsAny<CryptographicException>(
-            () => HostingExtensions.ComputeKid(missing));
-    }
-
-    // --- helpers ----------------------------------------------------
-
-    /// <summary>
-    /// Generate a throwaway self-signed RSA-2048 cert, export it
-    /// as PEM to a file inside the test temp dir, and return the
-    /// path. The out parameter receives the upper-case hex form
-    /// of the cert's SHA-1 thumbprint so tests can pin the
-    /// expected kid without re-implementing the helper.
-    /// </summary>
-    private string WriteSelfSignedCertRsa(out string thumbHex)
-    {
-        using var rsa = RSA.Create(2048);
-        var req = new CertificateRequest(
-            "CN=yavsc-test",
-            rsa,
-            HashAlgorithmName.SHA256,
-            RSASignaturePadding.Pkcs1);
-        using var cert = req.CreateSelfSigned(
-            DateTimeOffset.UtcNow.AddDays(-1),
-            DateTimeOffset.UtcNow.AddYears(1));
-
-        // Capture the thumbprint before exporting — the cert is
-        // disposed by `using` and the exported PEM is what the
-        // helper will read.
-        thumbHex = Convert.ToHexString(cert.GetCertHash());
-
-        var path = Path.Combine(_tempDir, "cert-" + Guid.NewGuid().ToString("N") + ".pem");
-        File.WriteAllText(path, cert.ExportCertificatePem());
-        return path;
-    }
-}
diff --git a/src/Yavsc.Org/AssemblyInfo.cs b/src/Yavsc.Org/AssemblyInfo.cs
index c29735e1..55821c70 100644
--- a/src/Yavsc.Org/AssemblyInfo.cs
+++ b/src/Yavsc.Org/AssemblyInfo.cs
@@ -1,9 +1,3 @@
 using Microsoft.Extensions.Localization;
-using System.Runtime.CompilerServices;
 
 [assembly: RootNamespace("Yavsc")]
-
-// Expose internals to the Yavsc.Org.Tests project so unit tests can
-// reach the signing-credential loader (LoadSigningCredentials / kid
-// derivation) without going through the full IdentityServer boot.
-[assembly: InternalsVisibleTo("Yavsc.Org.Tests")]
diff --git a/src/Yavsc.Org/Extensions/HostingExtensions.cs b/src/Yavsc.Org/Extensions/HostingExtensions.cs
index 6fc5b9c4..b29f37ce 100644
--- a/src/Yavsc.Org/Extensions/HostingExtensions.cs
+++ b/src/Yavsc.Org/Extensions/HostingExtensions.cs
@@ -478,20 +478,6 @@ public static class HostingExtensions
         // Validate the cert is readable (used downstream for token
         // audience/subject validation; signing itself uses the key).
 
-        // Derive a stable KeyId from the certificate's SHA-1
-        // thumbprint (the default for X509Certificate2.GetCertHash()).
-        // Without an explicit KeyId, IdentityServer emits JWTs without
-        // a 'kid' header and the JWKS without per-key identifiers,
-        // which breaks signature validation on resource servers (they
-        // cannot match a token to a key in the JWKS, they fail with
-        // IDX10500 "The signature key was not found"). Truncating the
-        // 40-hex-char SHA-1 to 16 hex chars is enough to be globally
-        // unique within a deployment and keeps the JWT header compact.
-        // The thumbprint changes on cert renewal, which is the desired
-        // behaviour: old tokens age out, resource servers refresh
-        // their JWKS cache for the new kid.
-        var kid = ComputeKid(certPath);
-
         string keyPem = File.ReadAllText(keyPath);
 
         // BouncyCastle's PemReader accepts every flavour of unencrypted
@@ -527,7 +513,7 @@ public static class HostingExtensions
 #pragma warning disable CA1416 // Valider la compatibilité de la plateforme
                     var rsaDotNet = DotNetUtilities.ToRSA(rsa);
 #pragma warning restore CA1416 // Valider la compatibilité de la plateforme
-                    var key = new RsaSecurityKey(rsaDotNet) { KeyId = kid };
+                    var key = new RsaSecurityKey(rsaDotNet);
                     return new SigningCredentials(key, SecurityAlgorithms.RsaSha256);
                 }
             case ECPrivateKeyParameters ec:
@@ -539,7 +525,7 @@ public static class HostingExtensions
                     };
                     var ecdsa = ECDsa.Create();
                     ecdsa.ImportParameters(ecParams);
-                    var key = new ECDsaSecurityKey(ecdsa) { KeyId = kid };
+                    var key = new ECDsaSecurityKey(ecdsa);
                     return new SigningCredentials(key, SecurityAlgorithms.EcdsaSha256);
                 }
             default:
@@ -549,34 +535,6 @@ public static class HostingExtensions
         }
     }
 
-    /// <summary>
-    /// Derive the <c>kid</c> used to identify the signing key in the
-    /// JWT header and the JWKS. Takes the first 16 hex characters of
-    /// the certificate's SHA-1 thumbprint. See the inline rationale in
-    /// <see cref="LoadSigningCredentialsInner"/> for why this is
-    /// needed (IdentityServer8 + IDX10500).
-    /// </summary>
-    /// <remarks>
-    /// Internal so unit tests in <c>Yavsc.Org.Tests</c> can exercise
-    /// the truncation/encoding without going through the full PEM /
-    /// BouncyCastle pipeline. The input is a path rather than a
-    /// pre-loaded <see cref="X509Certificate2"/> to match the
-    /// production call site.
-    /// </remarks>
-    internal static string ComputeKid(string certPath)
-    {
-        // X509CertificateLoader is the .NET 9+ replacement for the
-        // obsolete `new X509Certificate2(string)` ctor (SYSLIB0057).
-        // Same on-disk format (PEM or DER), same thumbprint, just
-        // doesn't trip the obsolete-API warning at build time.
-        var certForKid = X509CertificateLoader.LoadCertificateFromFile(certPath);
-        var certHash = certForKid.GetCertHash();
-        // GetCertHash() returns a SHA-1 thumbprint (20 bytes, 40 hex
-        // chars). Truncating to 16 hex chars keeps the JWT header
-        // compact; Math.Min guards against an unexpected short hash.
-        return Convert.ToHexString(certHash)[..Math.Min(16, certHash.Length * 2)];
-    }
-
     /// <summary>
     /// Map a BouncyCastle <see cref="ECDomainParameters"/> to a
     /// <see cref="ECCurve"/> that <see cref="ECDsa.ImportParameters"/>