diff --git a/OpenNest.Desktop.Tests/DesktopOptionsTests.cs b/OpenNest.Desktop.Tests/DesktopOptionsTests.cs
new file mode 100644
index 00000000..9029432a
--- /dev/null
+++ b/OpenNest.Desktop.Tests/DesktopOptionsTests.cs
@@ -0,0 +1,336 @@
+using OpenNest.Data;
+using OpenNest.Engine.Fill;
+using OpenNest.Engine.Strategies;
+
+namespace OpenNest.Desktop.Tests;
+
+public class DesktopOptionsTests
+{
+    // As the WinForms app stores them in user-settings.json.
+    private static Dictionary<string, string> WinFormsSaved() => new()
+    {
+        ["CreateNewNestOnOpen"] = "False",
+        ["AutoSizePlateFactor"] = "0.25",
+        ["CuttingPlanEffort"] = "2.5",
+        ["ActiveColorScheme"] = "Dark",
+        ["ClonePlacementOrder"] = "VerticalFirst",
+        ["DisabledStrategies"] = "Pairs,Extents",
+        ["UpdateIncludeDevBuilds"] = "True",
+        ["UpdateFeedUrl"] = "http://feed.example/releases",
+        ["LastFeedrate"] = "250",
+    };
+
+    [Fact]
+    public void Read_TheWinFormsValues()
+    {
+        var options = DesktopOptions.Read(WinFormsSaved());
+
+        Assert.False(options.CreateNewNestOnOpen);
+        Assert.Equal(0.25, options.AutoSizePlateFactor);
+        Assert.Equal(2.5, options.CuttingPlanEffort);
+        Assert.Equal("Dark", options.ColorScheme);
+        Assert.Equal(SettleOrder.VerticalFirst, options.ClonePlacementOrder);
+        Assert.Equal(new[] { "Extents", "Pairs" }, options.DisabledStrategies.OrderBy(n => n));
+        Assert.True(options.UpdateIncludeDevBuilds);
+    }
+
+    [Fact]
+    public void Read_NothingSaved_IsTheWinFormsDefaults()
+    {
+        var options = DesktopOptions.Read(new Dictionary<string, string>());
+
+        Assert.True(options.CreateNewNestOnOpen);
+        Assert.Equal(0.5, options.AutoSizePlateFactor);
+        Assert.Equal(1.0, options.CuttingPlanEffort);
+        Assert.Equal("Classic", options.ColorScheme);
+        Assert.Equal(SettleOrder.ClosestToCorner, options.ClonePlacementOrder);
+        Assert.Empty(options.DisabledStrategies);
+        Assert.False(options.UpdateIncludeDevBuilds);
+    }
+
+    [Fact]
+    public void Read_UnreadableValues_AreTheWinFormsDefaults()
+    {
+        var options = DesktopOptions.Read(new Dictionary<string, string>
+        {
+            ["CreateNewNestOnOpen"] = "maybe",
+            ["AutoSizePlateFactor"] = "half",
+            ["CuttingPlanEffort"] = "",
+            ["ClonePlacementOrder"] = "Sideways",
+            ["DisabledStrategies"] = " , ,",
+            ["UpdateIncludeDevBuilds"] = "1",
+        });
+
+        Assert.Equal(DesktopOptions.Defaults with { DisabledStrategies = options.DisabledStrategies }, options);
+        Assert.Empty(options.DisabledStrategies);
+    }
+
+    [Fact]
+    public void WriteTo_GivesBackTheWinFormsTextUnchanged_AndKeepsOtherSettings()
+    {
+        var stored = WinFormsSaved();
+
+        var written = new Dictionary<string, string>(stored);
+        DesktopOptions.Read(stored).WriteTo(written);
+
+        // The set is written back in its own order; the rest is the stored text.
+        Assert.Equal(
+            FillStrategyOptions.ParseDisabled(stored["DisabledStrategies"]),
+            FillStrategyOptions.ParseDisabled(written["DisabledStrategies"]));
+        written["DisabledStrategies"] = stored["DisabledStrategies"];
+        Assert.Equal(stored, written);
+    }
+
+    [Fact]
+    public void WriteTo_TheWinFormsTextForms_AndNeverTheFeedUrl()
+    {
+        var written = new Dictionary<string, string>();
+
+        new DesktopOptions
+        {
+            AutoSizePlateFactor = 0.1,
+            CuttingPlanEffort = 3,
+            ColorScheme = "",
+            DisabledStrategies = new[] { "Row" },
+        }.WriteTo(written);
+
+        Assert.Equal("True", written["CreateNewNestOnOpen"]);
+        Assert.Equal("False", written["UpdateIncludeDevBuilds"]);
+        Assert.Equal("0.1", written["AutoSizePlateFactor"]);
+        Assert.Equal("3", written["CuttingPlanEffort"]);
+        Assert.Equal("Classic", written["ActiveColorScheme"]);
+        Assert.Equal("ClosestToCorner", written["ClonePlacementOrder"]);
+        Assert.Equal("Row", written["DisabledStrategies"]);
+        Assert.False(written.ContainsKey("UpdateFeedUrl"));
+    }
+
+    [Theory]
+    [InlineData(0.1, 0.5)]
+    [InlineData(25.0, 10.0)]
+    [InlineData(double.NaN, 1.0)]
+    [InlineData(4.0, 4.0)]
+    public void CuttingPlanEffortForEditing_IsTheValuePlanCuttingUses(double saved, double shown)
+    {
+        Assert.Equal(shown, new DesktopOptions { CuttingPlanEffort = saved }.CuttingPlanEffortForEditing);
+    }
+
+    [Theory]
+    [InlineData(-1.0, 0.0)]
+    [InlineData(250.0, 100.0)]
+    [InlineData(double.PositiveInfinity, 0.5)]
+    [InlineData(0.375, 0.375)]
+    public void AutoSizePlateFactorForEditing_IsWithinTheBoxRange(double saved, double shown)
+    {
+        Assert.Equal(shown, new DesktopOptions { AutoSizePlateFactor = saved }.AutoSizePlateFactorForEditing);
+    }
+
+    [Fact]
+    public void ColorSchemeIndex_ExactName_ElseTheFirst()
+    {
+        var names = new[] { "Classic", "Pastel", "Dark" };
+
+        Assert.Equal(2, new DesktopOptions { ColorScheme = "Dark" }.ColorSchemeIndex(names));
+        Assert.Equal(0, new DesktopOptions { ColorScheme = "dark" }.ColorSchemeIndex(names));
+        Assert.Equal(0, new DesktopOptions { ColorScheme = "Gone" }.ColorSchemeIndex(names));
+    }
+
+    [Fact]
+    public void ClonePlacement_ChoicesInComboOrder()
+    {
+        Assert.Equal(
+            new[] { SettleOrder.ClosestToCorner, SettleOrder.HorizontalFirst, SettleOrder.VerticalFirst },
+            ClonePlacement.Choices.Select(c => c.Order));
+        Assert.Equal(1, ClonePlacement.IndexOf(SettleOrder.HorizontalFirst));
+        Assert.Equal(SettleOrder.VerticalFirst, ClonePlacement.At(2));
+        Assert.Equal(SettleOrder.ClosestToCorner, ClonePlacement.At(-1));
+    }
+
+    [Theory]
+    [InlineData("HorizontalFirst", SettleOrder.HorizontalFirst)]
+    [InlineData("7", SettleOrder.ClosestToCorner)]
+    [InlineData(null, SettleOrder.ClosestToCorner)]
+    [InlineData("", SettleOrder.ClosestToCorner)]
+    public void ClonePlacement_Parse_UnknownIsClosestToOrigin(string? stored, SettleOrder expected)
+    {
+        Assert.Equal(expected, ClonePlacement.Parse(stored!));
+    }
+
+    [Fact]
+    public void FillStrategyOptions_ParseIgnoresCaseAndBlanks()
+    {
+        var names = FillStrategyOptions.ParseDisabled(" pairs , ,Row,ROW");
+
+        Assert.Equal(2, names.Count);
+        Assert.Contains("Pairs", names);
+        Assert.Contains("row", names);
+        Assert.Empty(FillStrategyOptions.ParseDisabled(null!));
+    }
+
+    [Fact]
+    public void FillStrategyOptions_RowsListEveryStrategyInPipelineOrder()
+    {
+        Assert.Equal(
+            FillStrategyRegistry.AllStrategies.Select(s => (s.Name, s.Phase, s.Order)),
+            FillStrategyOptions.Rows.Select(r => (r.Name, r.Phase, r.Order)));
+    }
+
+    [Fact]
+    public void UpdateFeed_SavesTheNormalizedUrl()
+    {
+        string? saved = null;
+
+        var (notice, url) = UpdateFeedOption.Save("  https://feed.example/opennest/  ", u => saved = u);
+
+        Assert.Equal("https://feed.example/opennest", url);
+        Assert.Equal(url, saved);
+        Assert.Equal(OptionNoticeKind.Information, notice.Kind);
+        Assert.Contains("Restart OpenNest", notice.Text);
+    }
+
+    [Fact]
+    public void UpdateFeed_BlankClearsIt()
+    {
+        string? saved = null;
+
+        var (notice, url) = UpdateFeedOption.Save("   ", u => saved = u);
+
+        Assert.Equal("", url);
+        Assert.Equal("", saved);
+        Assert.StartsWith("Update feed URL cleared.", notice.Text);
+    }
+
+    [Theory]
+    [InlineData("ftp://feed.example")]
+    [InlineData("not a url")]
+    public void UpdateFeed_RefusesAnythingButHttp(string text)
+    {
+        var called = false;
+
+        var (notice, url) = UpdateFeedOption.Save(text, _ => called = true);
+
+        Assert.Null(url);
+        Assert.False(called);
+        Assert.Equal(OptionNoticeKind.Warning, notice.Kind);
+    }
+
+    [Fact]
+    public void UpdateFeed_AFailedWriteIsReported()
+    {
+        var (notice, url) = UpdateFeedOption.Save("http://feed", _ => throw new IOException("disk full"));
+
+        Assert.Null(url);
+        Assert.Equal(OptionNoticeKind.Error, notice.Kind);
+        Assert.Contains("disk full", notice.Text);
+    }
+
+    [Fact]
+    public void UpdateFeed_ReadsTheSavedUrl()
+    {
+        Assert.Equal("http://feed.example/releases", UpdateFeedOption.Read(WinFormsSaved()));
+        Assert.Equal("", UpdateFeedOption.Read(new Dictionary<string, string>()));
+    }
+
+    [Fact]
+    public void ServerUrl_RefusesAnInvalidUrl()
+    {
+        var (notice, url) = NestServerUrlOption.Save("", _ => throw new InvalidOperationException());
+
+        Assert.Null(url);
+        Assert.Equal(OptionNoticeKind.Warning, notice.Kind);
+        Assert.Equal("Enter a valid http or https server URL.", notice.Text);
+    }
+
+    [Fact]
+    public void ServerUrl_AFailedWriteIsReported()
+    {
+        var (notice, url) = NestServerUrlOption.Save("http://nest:8080", _ => throw new IOException("locked"));
+
+        Assert.Null(url);
+        Assert.Equal(OptionNoticeKind.Error, notice.Kind);
+        Assert.Equal("Could not save the server URL: locked", notice.Text);
+    }
+
+    [Fact]
+    public void ServerUrl_SaveToFileKeepsTheStorageMode()
+    {
+        var directory = Path.Combine(Path.GetTempPath(), "opennest-options-" + Guid.NewGuid().ToString("N"));
+        var path = Path.Combine(directory, "storage.json");
+        try
+        {
+            new NestStorageSettings { Mode = NestStorageMode.Database, ServerUrl = "http://old:8080" }.Save(path);
+
+            var (notice, url) = NestServerUrlOption.Save(" http://nest.lan:8080/ ",
+                u => NestServerUrlOption.SaveToFile(path, u));
+
+            Assert.Equal(OptionNoticeKind.Information, notice.Kind);
+            Assert.Equal("http://nest.lan:8080", url);
+            var saved = NestStorageSettings.Load(path);
+            Assert.Equal(NestStorageMode.Database, saved.Mode);
+            Assert.Equal("http://nest.lan:8080", saved.ServerUrl);
+        }
+        finally
+        {
+            if (Directory.Exists(directory))
+                Directory.Delete(directory, true);
+        }
+    }
+
+    [Fact]
+    public void ServerUrl_SaveToFileWithNoFileIsFileMode()
+    {
+        var directory = Path.Combine(Path.GetTempPath(), "opennest-options-" + Guid.NewGuid().ToString("N"));
+        var path = Path.Combine(directory, "storage.json");
+        try
+        {
+            var saved = NestServerUrlOption.SaveToFile(path, "http://nest:8080");
+
+            Assert.Equal(NestStorageMode.File, saved.Mode);
+            Assert.Equal("http://nest:8080", NestStorageSettings.Load(path).ServerUrl);
+        }
+        finally
+        {
+            if (Directory.Exists(directory))
+                Directory.Delete(directory, true);
+        }
+    }
+}
+
+// Applying options changes the process-wide strategy set and colour scheme.
+[Collection(ColorSchemeState.Collection)]
+public class DesktopOptionsApplyTests : IDisposable
+{
+    private readonly ColorSchemeState saved = new();
+    private readonly string[] disabledBefore = FillStrategyRegistry.DisabledNames.ToArray();
+
+    public void Dispose()
+    {
+        FillStrategyOptions.Apply(disabledBefore);
+        saved.Restore();
+    }
+
+    [Fact]
+    public void Apply_DisablesExactlyTheSavedStrategies_AndUsesTheScheme()
+    {
+        var all = FillStrategyRegistry.AllStrategies.Select(s => s.Name).ToArray();
+        FillStrategyRegistry.Disable(all[0]);
+
+        new DesktopOptions
+        {
+            ColorScheme = "Dark",
+            DisabledStrategies = new[] { all[1].ToUpperInvariant() },
+        }.Apply();
+
+        Assert.Equal(all.Where(n => n != all[1]), FillStrategyRegistry.Strategies.Select(s => s.Name));
+        Assert.Equal("Dark", ColorScheme.Default.Name);
+    }
+
+    [Fact]
+    public void ApplySaved_NoneSavedEnablesEveryStrategy()
+    {
+        FillStrategyRegistry.Disable(FillStrategyRegistry.AllStrategies[0].Name);
+
+        FillStrategyOptions.ApplySaved(new Dictionary<string, string>());
+
+        Assert.Equal(FillStrategyRegistry.AllStrategies, FillStrategyRegistry.Strategies);
+    }
+}
diff --git a/OpenNest.Desktop/DesktopOptions.cs b/OpenNest.Desktop/DesktopOptions.cs
new file mode 100644
index 00000000..25179504
--- /dev/null
+++ b/OpenNest.Desktop/DesktopOptions.cs
@@ -0,0 +1,317 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenNest.Data;
+using OpenNest.Engine;
+using OpenNest.Engine.CuttingPlanning;
+using OpenNest.Engine.Fill;
+using OpenNest.Engine.Strategies;
+
+namespace OpenNest.Desktop;
+
+/// <summary>
+/// The values Tools &gt; Options saves with its Save button, under the WinForms user-setting
+/// names both desktop apps share in user-settings.json. A missing or unreadable value is its
+/// WinForms default. The update feed URL and the nest server URL have their own buttons
+/// (<see cref="UpdateFeedOption"/>, <see cref="NestServerUrlOption"/>), so Save leaves them alone.
+/// </summary>
+public sealed record DesktopOptions
+{
+    public const string CreateNewNestOnOpenName = "CreateNewNestOnOpen";
+    public const string AutoSizePlateFactorName = "AutoSizePlateFactor";
+    public const string CuttingPlanEffortName = "CuttingPlanEffort";
+    public const string ClonePlacementOrderName = "ClonePlacementOrder";
+    public const string DisabledStrategiesName = "DisabledStrategies";
+    public const string UpdateIncludeDevBuildsName = "UpdateIncludeDevBuilds";
+
+    /// <summary>The auto-size factor's range and step, as the WinForms box allows.</summary>
+    public const double AutoSizePlateFactorMinimum = 0;
+    public const double AutoSizePlateFactorMaximum = 100;
+    public const double AutoSizePlateFactorIncrement = 0.125;
+    public const int AutoSizePlateFactorDecimals = 4;
+
+    /// <summary>Cut planning effort's step; its range is Plan Cutting's budget multiplier range.</summary>
+    public const double CuttingPlanEffortIncrement = 0.1;
+
+    public static double CuttingPlanEffortMinimum => CuttingPlanBatch.MinimumBudgetMultiplier;
+    public static double CuttingPlanEffortMaximum => CuttingPlanBatch.MaximumBudgetMultiplier;
+
+    /// <summary>The WinForms setting defaults.</summary>
+    public static DesktopOptions Defaults { get; } = new();
+
+    /// <summary>Create a new nest when the app starts.</summary>
+    public bool CreateNewNestOnOpen { get; init; } = true;
+
+    /// <summary>The amount Resize Plate rounds the plate size up to.</summary>
+    public double AutoSizePlateFactor { get; init; } = 0.5;
+
+    /// <summary>Plan Cutting's search budget multiplier (1 is normal).</summary>
+    public double CuttingPlanEffort { get; init; } = CuttingPlanBatch.DefaultBudgetMultiplier;
+
+    /// <summary>The colour scheme's name, as <see cref="ColorSchemeRegistry.SettingName"/> stores it.</summary>
+    public string ColorScheme { get; init; } = ColorSchemeRegistry.DefaultSchemeName;
+
+    /// <summary>Which way Shift+click and Ctrl+click clones push the copy.</summary>
+    public SettleOrder ClonePlacementOrder { get; init; } = SettleOrder.ClosestToCorner;
+
+    /// <summary>Fill strategies left out of the pipeline, stored comma-separated by name.</summary>
+    public IReadOnlyCollection<string> DisabledStrategies { get; init; } = Array.Empty<string>();
+
+    /// <summary>Check the rolling development-build release as well as stable releases.</summary>
+    public bool UpdateIncludeDevBuilds { get; init; }
+
+    /// <summary>The saved values; one missing or unreadable is its WinForms default.</summary>
+    public static DesktopOptions Read(IReadOnlyDictionary<string, string> settings)
+    {
+        ArgumentNullException.ThrowIfNull(settings);
+        return new DesktopOptions
+        {
+            CreateNewNestOnOpen = UserSettingText.ReadBool(settings, CreateNewNestOnOpenName, Defaults.CreateNewNestOnOpen),
+            AutoSizePlateFactor = UserSettingText.ReadDouble(settings, AutoSizePlateFactorName, Defaults.AutoSizePlateFactor),
+            CuttingPlanEffort = UserSettingText.ReadDouble(settings, CuttingPlanEffortName, Defaults.CuttingPlanEffort),
+            ColorScheme = ColorSchemeRegistry.SavedSchemeName(settings),
+            ClonePlacementOrder = ClonePlacement.Parse(
+                UserSettingText.ReadString(settings, ClonePlacementOrderName, null)),
+            DisabledStrategies = FillStrategyOptions.ParseDisabled(
+                UserSettingText.ReadString(settings, DisabledStrategiesName, "")),
+            UpdateIncludeDevBuilds = UserSettingText.ReadBool(settings, UpdateIncludeDevBuildsName, Defaults.UpdateIncludeDevBuilds),
+        };
+    }
+
+    /// <summary>
+    /// Stores the values Save writes, in the WinForms text form; other settings are kept, and
+    /// the cut planning effort is stored as entered (Plan Cutting clamps it when it reads it).
+    /// </summary>
+    public void WriteTo(IDictionary<string, string> settings)
+    {
+        ArgumentNullException.ThrowIfNull(settings);
+        settings[CreateNewNestOnOpenName] = UserSettingText.Format(CreateNewNestOnOpen);
+        settings[UpdateIncludeDevBuildsName] = UserSettingText.Format(UpdateIncludeDevBuilds);
+        settings[AutoSizePlateFactorName] = UserSettingText.Format(AutoSizePlateFactor);
+        settings[CuttingPlanEffortName] = UserSettingText.Format(CuttingPlanEffort);
+        settings[ColorSchemeRegistry.SettingName] = string.IsNullOrEmpty(ColorScheme)
+            ? ColorSchemeRegistry.DefaultSchemeName
+            : ColorScheme;
+        settings[ClonePlacementOrderName] = ClonePlacementOrder.ToString();
+        settings[DisabledStrategiesName] = FillStrategyOptions.FormatDisabled(DisabledStrategies);
+    }
+
+    /// <summary>The colour schemes to choose from: the built-ins, then those in Schemes.</summary>
+    public static IReadOnlyList<string> ColorSchemeNames =>
+        ColorSchemeRegistry.AllSchemes.Select(s => s.Name).ToList();
+
+    /// <summary>
+    /// The index of the saved scheme in <paramref name="names"/> (exact name), or the first
+    /// scheme when it is no longer there, as the WinForms combo selects it.
+    /// </summary>
+    public int ColorSchemeIndex(IReadOnlyList<string> names)
+    {
+        ArgumentNullException.ThrowIfNull(names);
+        for (var i = 0; i < names.Count; i++)
+        {
+            if (names[i] == ColorScheme)
+                return i;
+        }
+        return 0;
+    }
+
+    /// <summary>The auto-size factor as the Options box shows it: within its range.</summary>
+    public double AutoSizePlateFactorForEditing =>
+        double.IsFinite(AutoSizePlateFactor)
+            ? System.Math.Clamp(AutoSizePlateFactor, AutoSizePlateFactorMinimum, AutoSizePlateFactorMaximum)
+            : Defaults.AutoSizePlateFactor;
+
+    /// <summary>The cut planning effort as the Options box shows it: the value Plan Cutting uses.</summary>
+    public double CuttingPlanEffortForEditing => CuttingPlanBatch.ClampBudgetMultiplier(CuttingPlanEffort);
+
+    /// <summary>
+    /// Applies what takes effect without a restart: the fill strategy enablement and the colour
+    /// scheme (whose <see cref="ColorSchemeRegistry.Applied"/> lets each front end recolour and
+    /// repaint). Run after Save and, from the saved settings, at startup.
+    /// </summary>
+    public void Apply()
+    {
+        FillStrategyOptions.Apply(DisabledStrategies);
+        ColorSchemeRegistry.Apply(ColorSchemeRegistry.Get(ColorScheme));
+    }
+}
+
+/// <summary>The Options choices for Shift+click and Ctrl+click clone placement, in combo order.</summary>
+public static class ClonePlacement
+{
+    public static IReadOnlyList<(SettleOrder Order, string Text)> Choices { get; } = new[]
+    {
+        (SettleOrder.ClosestToCorner, "Closest to origin"),
+        (SettleOrder.HorizontalFirst, "Push horizontally first"),
+        (SettleOrder.VerticalFirst, "Push vertically first"),
+    };
+
+    /// <summary>The stored enum name's order; an unknown name is the closest-to-origin search.</summary>
+    public static SettleOrder Parse(string stored) =>
+        Enum.TryParse<SettleOrder>(stored, out var order) && Enum.IsDefined(order)
+            ? order
+            : SettleOrder.ClosestToCorner;
+
+    /// <summary>The combo index of <paramref name="order"/>, the first for one not listed.</summary>
+    public static int IndexOf(SettleOrder order)
+    {
+        for (var i = 0; i < Choices.Count; i++)
+        {
+            if (Choices[i].Order == order)
+                return i;
+        }
+        return 0;
+    }
+
+    /// <summary>The order at a combo index; no selection is the first choice.</summary>
+    public static SettleOrder At(int index) => Choices[System.Math.Clamp(index, 0, Choices.Count - 1)].Order;
+}
+
+/// <summary>A fill strategy as the Options grid lists it.</summary>
+public sealed record FillStrategyRow(string Name, NestPhase Phase, int Order);
+
+/// <summary>
+/// The Options fill strategy grid and the DisabledStrategies setting: names separated by commas,
+/// matched without regard to case, applied to <see cref="FillStrategyRegistry"/>.
+/// </summary>
+public static class FillStrategyOptions
+{
+    /// <summary>Every built-in strategy, in pipeline order.</summary>
+    public static IReadOnlyList<FillStrategyRow> Rows =>
+        FillStrategyRegistry.AllStrategies.Select(s => new FillStrategyRow(s.Name, s.Phase, s.Order)).ToList();
+
+    /// <summary>The names in a stored value; blank entries are skipped.</summary>
+    public static HashSet<string> ParseDisabled(string value)
+    {
+        if (string.IsNullOrWhiteSpace(value))
+            return new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        return new HashSet<string>(
+            value.Split(',').Select(s => s.Trim()).Where(s => s.Length > 0),
+            StringComparer.OrdinalIgnoreCase);
+    }
+
+    /// <summary>The stored form of <paramref name="names"/>.</summary>
+    public static string FormatDisabled(IEnumerable<string> names) =>
+        names == null ? "" : string.Join(",", names);
+
+    /// <summary>Re-enables every strategy, then disables <paramref name="disabled"/>.</summary>
+    public static void Apply(IEnumerable<string> disabled)
+    {
+        FillStrategyRegistry.Enable(FillStrategyRegistry.AllStrategies.Select(s => s.Name).ToArray());
+        var names = disabled?.ToArray() ?? Array.Empty<string>();
+        if (names.Length > 0)
+            FillStrategyRegistry.Disable(names);
+    }
+
+    /// <summary>Applies the DisabledStrategies value stored in <paramref name="settings"/>.</summary>
+    public static void ApplySaved(IReadOnlyDictionary<string, string> settings) =>
+        Apply(ParseDisabled(UserSettingText.ReadString(settings, DesktopOptions.DisabledStrategiesName, "")));
+}
+
+public enum OptionNoticeKind
+{
+    Information,
+    Warning,
+    Error,
+}
+
+/// <summary>What to tell the user after an Options button, and how.</summary>
+public sealed record OptionNotice(string Title, string Text, OptionNoticeKind Kind);
+
+/// <summary>
+/// Tools &gt; Options &gt; Set / Change Server: the nest server URL in storage.json, keeping the
+/// storage mode (File / Database is chosen under File &gt; Storage Mode).
+/// </summary>
+public static class NestServerUrlOption
+{
+    public const string Title = "Server URL";
+
+    /// <summary>
+    /// Validates <paramref name="text"/> and passes the normalized URL to <paramref name="save"/>,
+    /// which writes storage.json; returns what to tell the user and the URL saved (null when not).
+    /// </summary>
+    public static (OptionNotice Notice, string SavedUrl) Save(string text, Action<string> save)
+    {
+        ArgumentNullException.ThrowIfNull(save);
+        if (!NestStorageSettings.TryNormalizeServerUrl(text, out var url))
+            return (new OptionNotice(Title, "Enter a valid http or https server URL.", OptionNoticeKind.Warning), null);
+
+        try
+        {
+            save(url);
+            return (new OptionNotice(Title, "Server URL saved. Storage mode has not changed.",
+                OptionNoticeKind.Information), url);
+        }
+        catch (Exception ex)
+        {
+            return (new OptionNotice(Title, $"Could not save the server URL: {ex.Message}", OptionNoticeKind.Error), null);
+        }
+    }
+
+    /// <summary>Writes <paramref name="serverUrl"/> into the storage.json at <paramref name="path"/>, keeping its mode.</summary>
+    public static NestStorageSettings SaveToFile(string path, string serverUrl)
+    {
+        var next = new NestStorageSettings
+        {
+            Mode = NestStorageSettings.Load(path).Mode,
+            ServerUrl = serverUrl,
+        };
+        next.Save(path);
+        return NestStorageSettings.Load(path);
+    }
+}
+
+/// <summary>
+/// Tools &gt; Options &gt; Save Feed URL: the UpdateFeedUrl user setting. Blank means the default
+/// source: the nest server's mirror in Database mode (GitHub Releases if it has none), otherwise
+/// GitHub Releases. A change takes effect after a restart.
+/// </summary>
+public static class UpdateFeedOption
+{
+    public const string SettingName = "UpdateFeedUrl";
+    public const string Title = "Update Feed URL";
+
+    /// <summary>The saved feed URL; blank (the default) when none.</summary>
+    public static string Read(IReadOnlyDictionary<string, string> settings) =>
+        UserSettingText.ReadString(settings, SettingName, "");
+
+    /// <summary>
+    /// Validates <paramref name="text"/> (blank clears it) and passes the normalized URL to
+    /// <paramref name="save"/>; returns what to tell the user and the URL saved (null when not).
+    /// </summary>
+    public static (OptionNotice Notice, string SavedUrl) Save(string text, Action<string> save)
+    {
+        ArgumentNullException.ThrowIfNull(save);
+        text = text?.Trim() ?? "";
+        string url;
+        string saved;
+        if (text.Length == 0)
+        {
+            url = "";
+            saved = "Update feed URL cleared. After a restart, updates come from "
+                + "the nest server's mirror in Database mode (GitHub Releases if it has none), "
+                + "otherwise from GitHub Releases.";
+        }
+        else if (NestStorageSettings.TryNormalizeServerUrl(text, out url))
+        {
+            saved = "Update feed URL saved. Restart OpenNest for the new feed to take effect.";
+        }
+        else
+        {
+            return (new OptionNotice(Title, "Enter a valid http or https feed URL, or clear the field to "
+                + "use the default source: the nest server's mirror in Database mode, "
+                + "otherwise GitHub Releases.", OptionNoticeKind.Warning), null);
+        }
+
+        try
+        {
+            save(url);
+            return (new OptionNotice(Title, saved, OptionNoticeKind.Information), url);
+        }
+        catch (Exception ex)
+        {
+            return (new OptionNotice(Title, $"Could not save the update feed URL: {ex.Message}", OptionNoticeKind.Error), null);
+        }
+    }
+}