Add invoice provision-period PDF handling

Normalize invoice provision periods in PDF generation, switch admin labels between single-date and range modes, add end-to-end tests, update package and frontend bundle versions, and note the invoice lifecycle docs update.

Fuchs.Tests/DraftSessionConcurrencyTests.cs

@@ -0,0 +1,388 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Fuchs.intranet;
+using Fuchs.Services;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging.Abstractions;
+using MigraDoc.DocumentObjectModel;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using OCORE.security;
+using Xunit;
+using static OCORE.OCORE_dictionaries;
+
+namespace Fuchs.Tests;
+
+/// <summary>
+/// The editor fires patches, state fetches, previews and saves concurrently for one draft token. The
+/// session payload (<c>JArray</c>/<c>JObject</c>, history list) is not thread-safe, so the draft
+/// services serialise every access on <c>SyncRoot</c> and hand out snapshots. Regression for the
+/// production "Collection was modified" crash in <c>InvoiceSetStructure.RecomputeLevels</c>
+/// (inv/dpatch, 2026-10-01). Flushes are additionally serialised on <c>FlushGate</c>: the
+/// create/update decision in <c>FlushToDbAsync</c> is a read-then-write across an await, so two
+/// overlapping saves of a new draft would otherwise both create a DB row.
+/// </summary>
+public class DraftSessionConcurrencyTests
+{
+    /// <summary>
+    /// Registration double: records every call, hands out a fresh id per <b>create</b> and echoes the
+    /// given id for an update — like the DB, so a duplicate create is visible as a second distinct id.
+    /// <see cref="Block"/>, when set, parks the first registration until released, which lets a test
+    /// pin down the exact interleaving instead of hoping for one.
+    /// </summary>
+    private sealed class FakeInvoiceService : IInvoiceService
+    {
+        private int _ids;
+        public readonly ConcurrentQueue<(bool change, string invId)> Calls = new();
+        public TaskCompletionSource? Block;
+        public readonly TaskCompletionSource Entered = new(TaskCreationOptions.RunContinuationsAsynchronously);
+        public Exception? Throw;
+
+        public async Task<FdsInvoiceData> RegisterInvoiceAsync(FdsInvoiceData invoice, bool change, string invId, string userAccountId, DatabaseSecurity dbSec)
+        {
+            Calls.Enqueue((change, invId));
+            Entered.TrySetResult();
+            if (Block != null) { var b = Block; Block = null; await b.Task; }
+            if (Throw != null) { var ex = Throw; Throw = null; throw ex; }
+            string id = change ? invId : "INV" + Interlocked.Increment(ref _ids);
+            invoice.InvoiceRegistration = new GenericObjectDictionary(new Dictionary<string, object> { ["Id"] = id });
+            return invoice;
+        }
+        public Task<FdsInvoiceData> LoadInvoiceAsync(string id, string u, DatabaseSecurity s) => throw new NotSupportedException();
+        public Task<Document> GenerateInvoicePdfAsync(FdsInvoiceData i, bool d) => Task.FromResult(new Document());
+        public Task<byte[]> RenderInvoicePdfBytesAsync(FdsInvoiceData i, bool d) => throw new NotSupportedException();
+        public Task<byte[]> StoreInvoiceDocumentFileAsync(FdsInvoiceData i, bool d, string u, DatabaseSecurity s) => throw new NotSupportedException();
+        public Task<byte[]?> GetInvoiceFileAsync(FdsInvoiceData i, bool d, fds.IFdsMfr m) => throw new NotSupportedException();
+    }
+
+    private sealed class FakeReminderService : IReminderService
+    {
+        private int _ids;
+        public readonly ConcurrentQueue<(bool change, string remId)> Calls = new();
+        public TaskCompletionSource? Block;
+        public readonly TaskCompletionSource Entered = new(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        public async Task<FdsReminderData> RegisterReminderAsync(FdsReminderData reminder, bool change, string remId, string userAccountId, DatabaseSecurity dbSec)
+        {
+            Calls.Enqueue((change, remId));
+            Entered.TrySetResult();
+            if (Block != null) { var b = Block; Block = null; await b.Task; }
+            string id = change ? remId : "REM" + Interlocked.Increment(ref _ids);
+            reminder.ReminderRegistration = new GenericObjectDictionary(new Dictionary<string, object> { ["Id"] = id });
+            return reminder;
+        }
+        public Document GenerateReminderPdf(FdsReminderData reminder, bool draft) => new();
+        public Task<FdsReminderData> LoadReminderAsync(string id, string u, DatabaseSecurity s) => throw new NotSupportedException();
+        public Task<byte[]> RenderReminderPdfBytesAsync(FdsReminderData r, bool d) => throw new NotSupportedException();
+        public Task<byte[]> StoreReminderDocumentFileAsync(FdsReminderData r, bool d, string u, DatabaseSecurity s) => throw new NotSupportedException();
+        public Task<byte[]> GetReminderFileAsync(FdsReminderData r, bool d, fds.IFdsMfr m, string u, DatabaseSecurity s) => throw new NotSupportedException();
+        public Task<(System.IO.FileInfo? file, byte[]? content)> GetStoredFileAsync(string id, string u, DatabaseSecurity s) => throw new NotSupportedException();
+    }
+
+    private static (InvoiceDraftEditService svc, FakeInvoiceService inv) NewInvoiceService()
+    {
+        var inv = new FakeInvoiceService();
+        return (new InvoiceDraftEditService(new InvoiceDraftCache(new ConfigurationBuilder().Build()), inv, NullLogger<InvoiceDraftEditService>.Instance), inv);
+    }
+
+    private static (ReminderDraftEditService svc, FakeReminderService rem) NewReminderService()
+    {
+        var rem = new FakeReminderService();
+        return (new ReminderDraftEditService(new ReminderDraftCache(new ConfigurationBuilder().Build()), rem, NullLogger<ReminderDraftEditService>.Instance), rem);
+    }
+
+    private static JObject InvoicePayload() => JObject.Parse(@"{
+        'admin':{'p13b':false,'type':'r','paymentterms':'10wd'},
+        'new':{'invoiceemail':'a@b.de','invoiceaddress':'Weg 1','invoicetitle':'Rechnung'},
+        'req':[{'Id':'1','text':'Auftrag','itm':[{'id':'900','typ':'set','vt':0,'vv':0,'vat':'19%'},
+                                              {'id':'901','typ':'material','vt':100,'vv':19,'vat':'19%','SetItmId':'900'}],
+                'items':[{'id':'900','type':'set','total_net':0,'vat':'19%'},{'id':'901','type':'material','total_net':100,'vat':'19%'}]}]
+    }");
+
+    private static JObject ReminderPayload() => JObject.Parse(@"{
+        'rem':{'invid':'INV5','type':'R','invoiceid':'R2026-1','invoicedate':'2026-06-01'},
+        'new':{'invoiceemail':'a@b.de','invoiceaddress':'Weg 1','subject':'Zahlungserinnerung','amount':119,'amount_payed':0}
+    }");
+
+    private static JObject Block(string id, decimal net) => JObject.Parse(
+        "{'Id':'" + id + "','text':'Auftrag " + id + "','itm':[{'id':'i" + id + "','typ':'material','vt':" + net + ",'vv':0,'vat':'19%'}]," +
+        "'items':[{'id':'i" + id + "','type':'material','total_net':" + net + ",'vat':'19%'}]}");
+
+    /// <summary>Runs <paramref name="writers"/> and <paramref name="readers"/> concurrently from a common start gate.</summary>
+    private static async Task RunConcurrently(IEnumerable<Action> writers, IEnumerable<Action> readers)
+    {
+        using var gate = new ManualResetEventSlim(false);
+        var tasks = writers.Concat(readers)
+            .Select(a => Task.Factory.StartNew(() => { gate.Wait(); a(); }, TaskCreationOptions.LongRunning))
+            .ToList();
+        gate.Set();
+        await Task.WhenAll(tasks);
+    }
+
+    private static Task WithTimeout(Task t) => t.WaitAsync(TimeSpan.FromSeconds(10));
+    private static Task<T> WithTimeout<T>(Task<T> t) => t.WaitAsync(TimeSpan.FromSeconds(10));
+
+    // ── payload lock ───────────────────────────────────────────────────────────
+    [Theory]
+    [InlineData("block.replace")]   // inserts new blocks → s.Req.Add (the crash: RecomputeLevels enumerating Req)
+    [InlineData("block.order")]     // s.Req.Clear() + re-add while others enumerate
+    public async Task ApplyPatch_ConcurrentPatchesAndStateReads_NeverThrowAndCountEveryPatch(string target)
+    {
+        const int patches = 200;
+        var (svc, _) = NewInvoiceService();
+        var s = svc.OpenFromPayload(InvoicePayload(), "user1");
+        if (target == "block.order")
+            for (int i = 0; i < 4; i++) svc.ApplyPatch(s.Token, new InvoiceDraftDelta { Target = "block.replace", Ref = "b" + i, Value = Block("b" + i, 10) });
+        int baseVersion = s.Version;
+
+        var writers = Enumerable.Range(0, patches).Select<int, Action>(i => () =>
+        {
+            var delta = target == "block.replace"
+                ? new InvoiceDraftDelta { Target = target, Ref = "n" + i, Value = Block("n" + i, 1) }
+                : new InvoiceDraftDelta { Target = target, Value = new JArray(i % 2 == 0 ? new[] { "b3", "b2", "1" } : new[] { "1", "b0", "b1" }) };
+            Assert.NotNull(svc.ApplyPatch(s.Token, delta));
+        });
+        var readers = Enumerable.Range(0, 50).Select<int, Action>(_ => () =>
+        {
+            for (int k = 0; k < 5; k++)
+            {
+                JsonConvert.SerializeObject(svc.BuildState(s));   // what JSONAsync does after BuildState returns
+                _ = svc.GetHistory(s.Token).Count;
+            }
+        });
+
+        await RunConcurrently(writers, readers);
+
+        // Every applied patch bumps the version exactly once and leaves one history entry (no lost
+        // updates). A reorder to the order that is already current is a no-op by design, so for
+        // block.order fewer than `patches` may apply.
+        Assert.Equal(s.Version, svc.GetHistory(s.Token).Count);
+        if (target == "block.order")
+        {
+            Assert.InRange(s.Version, baseVersion + 1, baseVersion + patches);
+            Assert.Equal(5, s.Req.Count);   // reorders never lose or duplicate a block
+        }
+        else
+        {
+            Assert.Equal(baseVersion + patches, s.Version);
+            Assert.Equal(1 + patches, s.Req.Count);
+            Assert.Equal(100m + patches, s.Sums.TotalNet);
+        }
+    }
+
+    [Fact]
+    public async Task RenderPreviewAndFlush_ConcurrentWithPatches_NeverThrowAndCreateExactlyOnce()
+    {
+        var (svc, inv) = NewInvoiceService();
+        var s = svc.OpenFromPayload(InvoicePayload(), "user1");
+        var results = new ConcurrentBag<DraftFlushResult<FdsInvoiceData>>();
+
+        var writers = Enumerable.Range(0, 100).Select<int, Action>(i => () =>
+            svc.ApplyPatch(s.Token, new InvoiceDraftDelta { Target = "block.replace", Ref = "n" + i, Value = Block("n" + i, 1) }));
+        var readers = Enumerable.Range(0, 20).Select<int, Action>(i => () =>
+        {
+            Assert.NotNull(svc.RenderPreviewAsync(s.Token).GetAwaiter().GetResult());
+            results.Add(svc.FlushToDbAsync(s.Token, "user1", null!).GetAwaiter().GetResult()!);
+        });
+
+        await RunConcurrently(writers, readers);
+
+        Assert.Equal(101, s.Req.Count);
+        // 20 overlapping saves of a brand-new draft: exactly one fds__createInvoice, every other save
+        // an update of that row — never a second orphaned invoice.
+        Assert.Equal(20, inv.Calls.Count);
+        Assert.Single(inv.Calls, c => !c.change);
+        Assert.Equal("INV1", s.InvId);
+        Assert.All(inv.Calls.Where(c => c.change), c => Assert.Equal("INV1", c.invId));
+        Assert.All(results, r => Assert.Equal("INV1", r.Data.Id));
+        Assert.Single(results, r => !r.Updated);
+    }
+
+    // ── flush gate ─────────────────────────────────────────────────────────────
+    [Fact]
+    public async Task FlushToDbAsync_SecondSaveOverlapsFirstRegistration_WaitsThenUpdatesInsteadOfCreating()
+    {
+        var (svc, inv) = NewInvoiceService();
+        var s = svc.OpenFromPayload(InvoicePayload(), "user1");
+        var block = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+        inv.Block = block;   // the fake clears Block once it has parked on it
+
+        var first = svc.FlushToDbAsync(s.Token, "user1", null!);
+        await WithTimeout(inv.Entered.Task);   // first save is inside the DB registration, InvId still empty
+        var second = svc.FlushToDbAsync(s.Token, "user1", null!);
+
+        // While the first registration is in flight the second save must not reach the registration at
+        // all (it would see the empty InvId and create a second row). A false pass here is possible
+        // only under pathological scheduling; a false failure is not.
+        await Task.Delay(150);
+        Assert.False(second.IsCompleted);
+        Assert.Single(inv.Calls);
+
+        block.SetResult();
+        var r1 = (await WithTimeout(first))!;
+        var r2 = (await WithTimeout(second))!;
+
+        Assert.Equal(new[] { (false, ""), (true, "INV1") }, inv.Calls.ToArray());
+        Assert.False(r1.Updated); Assert.Equal("INV1", r1.Data.Id);
+        Assert.True(r2.Updated);  Assert.Equal("INV1", r2.Data.Id);
+        Assert.Equal("INV1", s.InvId);
+    }
+
+    [Fact]
+    public async Task FlushToDbAsync_SecondSaveCarriesPatchesMadeDuringFirst()
+    {
+        var (svc, inv) = NewInvoiceService();
+        var s = svc.OpenFromPayload(InvoicePayload(), "user1");
+        var block = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+        inv.Block = block;   // the fake clears Block once it has parked on it
+
+        var first = svc.FlushToDbAsync(s.Token, "user1", null!);
+        await WithTimeout(inv.Entered.Task);
+        svc.ApplyPatch(s.Token, new InvoiceDraftDelta { Target = "email", Value = "neu@x.de" });   // edits are not blocked by a running save
+        var second = svc.FlushToDbAsync(s.Token, "user1", null!);
+        block.SetResult();
+
+        var r1 = (await WithTimeout(first))!;
+        var r2 = (await WithTimeout(second))!;
+
+        // The waiting save snapshots after it acquires the gate, so it persists the newer state —
+        // serialising never makes a save write stale data.
+        Assert.Equal("a@b.de", r1.Data.RawInvoiceEmail);
+        Assert.Equal("neu@x.de", r2.Data.RawInvoiceEmail);
+        Assert.True(r2.Updated);
+    }
+
+    [Fact]
+    public async Task FlushToDbAsync_RegistrationThrows_ReleasesGateAndNextSaveCreates()
+    {
+        var (svc, inv) = NewInvoiceService();
+        var s = svc.OpenFromPayload(InvoicePayload(), "user1");
+        inv.Throw = new InvalidOperationException("db down");
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => svc.FlushToDbAsync(s.Token, "user1", null!));
+
+        // The gate must be released by the failed save; the next one gets through and, since no id
+        // was committed, still runs as the create.
+        var r = (await WithTimeout(svc.FlushToDbAsync(s.Token, "user1", null!)))!;
+        Assert.False(r.Updated);
+        Assert.Equal("INV1", r.Data.Id);
+        Assert.Equal("INV1", s.InvId);
+        Assert.Equal(2, inv.Calls.Count);
+    }
+
+    [Fact]
+    public async Task FlushToDbAsync_UnknownToken_ReturnsNullWithoutRegistering()
+    {
+        var (svc, inv) = NewInvoiceService();
+        Assert.Null(await svc.FlushToDbAsync("ghost", "user1", null!));
+        Assert.Empty(inv.Calls);
+    }
+
+    [Fact]
+    public async Task ReminderFlushToDbAsync_SecondSaveOverlapsFirstRegistration_WaitsThenUpdatesInsteadOfCreating()
+    {
+        var (svc, rem) = NewReminderService();
+        var s = svc.OpenFromPayload(ReminderPayload(), "user1");
+        var block = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+        rem.Block = block;   // the fake clears Block once it has parked on it
+
+        var first = svc.FlushToDbAsync(s.Token, "user1", null!);
+        await WithTimeout(rem.Entered.Task);
+        var second = svc.FlushToDbAsync(s.Token, "user1", null!);
+        await Task.Delay(150);
+        Assert.False(second.IsCompleted);
+        Assert.Single(rem.Calls);
+
+        block.SetResult();
+        var r1 = (await WithTimeout(first))!;
+        var r2 = (await WithTimeout(second))!;
+
+        Assert.Equal(new[] { (false, ""), (true, "REM1") }, rem.Calls.ToArray());
+        Assert.False(r1.Updated); Assert.Equal("REM1", r1.Data.Id);
+        Assert.True(r2.Updated);  Assert.Equal("REM1", r2.Data.Id);
+        Assert.Equal("REM1", s.RemId);
+    }
+
+    [Fact]
+    public async Task ReminderFlushToDbAsync_ManyConcurrentSaves_CreateExactlyOnce()
+    {
+        var (svc, rem) = NewReminderService();
+        var s = svc.OpenFromPayload(ReminderPayload(), "user1");
+
+        await RunConcurrently(
+            Enumerable.Range(0, 20).Select<int, Action>(_ => () => svc.FlushToDbAsync(s.Token, "user1", null!).GetAwaiter().GetResult()),
+            Enumerable.Empty<Action>());
+
+        Assert.Equal(20, rem.Calls.Count);
+        Assert.Single(rem.Calls, c => !c.change);
+        Assert.Equal("REM1", s.RemId);
+    }
+
+    // ── snapshots ──────────────────────────────────────────────────────────────
+    [Fact]
+    public void BuildState_IsSnapshot_LaterPatchDoesNotChangeReturnedPayload()
+    {
+        var (svc, _) = NewInvoiceService();
+        var s = svc.OpenFromPayload(InvoicePayload(), "user1");
+        string before = JsonConvert.SerializeObject(svc.BuildState(s));
+        var state = svc.BuildState(s);
+
+        svc.ApplyPatch(s.Token, new InvoiceDraftDelta { Target = "block.replace", Ref = "x", Value = Block("x", 5) });
+        svc.ApplyPatch(s.Token, new InvoiceDraftDelta { Target = "email", Value = "neu@x.de" });
+
+        Assert.Equal(before, JsonConvert.SerializeObject(state));
+        Assert.Contains("neu@x.de", JsonConvert.SerializeObject(svc.BuildState(s)));
+    }
+
+    [Fact]
+    public void GetHistory_IsSnapshot_LaterPatchDoesNotGrowReturnedList()
+    {
+        var (svc, _) = NewInvoiceService();
+        var s = svc.OpenFromPayload(InvoicePayload(), "user1");
+        svc.ApplyPatch(s.Token, new InvoiceDraftDelta { Target = "email", Value = "x@y.de" });
+        var history = svc.GetHistory(s.Token);
+
+        svc.ApplyPatch(s.Token, new InvoiceDraftDelta { Target = "email", Value = "z@y.de" });
+
+        Assert.Single(history);
+        Assert.Equal(2, svc.GetHistory(s.Token).Count);
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("unknown-token")]
+    public void GetHistory_UnknownToken_ReturnsEmpty(string token)
+    {
+        Assert.Empty(NewInvoiceService().svc.GetHistory(token));
+        Assert.Empty(NewReminderService().svc.GetHistory(token));
+    }
+
+    [Fact]
+    public async Task ReminderApplyPatch_ConcurrentPatchesAndStateReads_NeverThrowAndCountEveryPatch()
+    {
+        const int patches = 200;
+        var (svc, _) = NewReminderService();
+        var s = svc.OpenFromPayload(ReminderPayload(), "user1");
+
+        var writers = Enumerable.Range(0, patches).Select<int, Action>(i => () =>
+            Assert.NotNull(svc.ApplyPatch(s.Token, new ReminderDraftDelta { Target = i % 2 == 0 ? "subject" : "amount_payed", Value = i % 2 == 0 ? "S" + i : "1" })));
+        var readers = Enumerable.Range(0, 50).Select<int, Action>(_ => () =>
+        {
+            for (int k = 0; k < 5; k++)
+            {
+                JsonConvert.SerializeObject(svc.BuildState(s));
+                _ = svc.GetHistory(s.Token).Count;
+            }
+        });
+
+        await RunConcurrently(writers, readers);
+
+        Assert.Equal(patches, s.Version);
+        Assert.Equal(patches, svc.GetHistory(s.Token).Count);
+        Assert.Equal(118m, s.Sums.AmountOpen);
+    }
+}

Fuchs.Tests/InvoiceDraftServiceTests.cs

@@ -169,7 +169,8 @@ public class InvoiceDraftServiceTests
         var result = await svc.FlushToDbAsync(s.Token, "user1", null!);
 
         Assert.NotNull(result);
-        Assert.Equal("INV42", result!.Id);
+        Assert.Equal("INV42", result!.Data.Id);
+        Assert.False(result.Updated);
         Assert.False(inv.LastChange);   // new draft (no prior InvId) → create, not update
         Assert.Equal("INV42", svc.Get(s.Token)!.InvId);
 
@@ -680,9 +681,10 @@ public class InvoiceDraftServiceTests
         payload["invid"] = "INV7";
         var s = svc.OpenFromPayload(payload, "user1");
 
-        await svc.FlushToDbAsync(s.Token, "user1", null!);
+        var result = await svc.FlushToDbAsync(s.Token, "user1", null!);
 
         Assert.True(inv.LastChange);   // prior InvId → update path
+        Assert.True(result!.Updated);
     }
 
     [Fact]

Fuchs.Tests/InvoicePdfProvisionPeriodTests.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Fuchs.intranet;
+using Fuchs.Notifications;
+using Fuchs.Services;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging.Abstractions;
+using MigraDoc.DocumentObjectModel;
+using Moq;
+using Xunit;
+
+namespace Fuchs.Tests;
+
+/// <summary>
+/// The stored Leistungsdatum / -zeitraum must reach the invoice PDF's admin block (it was never
+/// passed to the text blocks, so every invoice printed "Leistungszeitraum: -").
+/// </summary>
+public class InvoicePdfProvisionPeriodTests
+{
+    private sealed class NoHttp : IHttpClientFactory
+    {
+        public HttpClient CreateClient(string name) => throw new InvalidOperationException("no HTTP expected");
+    }
+
+    [Theory]
+    [InlineData("2026-06-18", "18.06.2026")]
+    [InlineData("2026-06-01 - 2026-06-30", "01.06.2026 - 30.06.2026")]
+    [InlineData("18.06.2026", "18.06.2026")]
+    [InlineData("01.06.2026 - 30.06.2026", "01.06.2026 - 30.06.2026")]
+    [InlineData("R2026-0258", "R2026-0258")]
+    [InlineData("", "")]
+    [InlineData(null, "")]
+    [InlineData("nach Absprache", "nach Absprache")]
+    public void ProvisionPeriodForDisplay_MixedFormats_ShowsGermanDates(string? input, string expected)
+    {
+        Assert.Equal(expected, InvoiceService.ProvisionPeriodForDisplay(input));
+    }
+
+    [Theory]
+    [InlineData("18.06.2026", "18.06.2026", "Leistungsdatum")]
+    [InlineData("01.06.2026 - 30.06.2026", "01.06.2026 - 30.06.2026", "Leistungszeitraum")]
+    [InlineData("2026-06-18", "18.06.2026", "Leistungsdatum")]
+    [InlineData("2026-06-01 - 2026-06-30", "01.06.2026 - 30.06.2026", "Leistungszeitraum")]
+    [InlineData("  18.06.2026  ", "18.06.2026", "Leistungsdatum")]
+    [InlineData("", "", "Leistungszeitraum")]
+    [InlineData(null, "", "Leistungszeitraum")]
+    public void ApplyProvisionPeriod_StoredValue_SetsGermanValueAndMatchingLabel(string? stored, string expectedValue, string expectedLabel)
+    {
+        var tb = new FuchsPdf.FdsTextBlocks();
+
+        InvoiceService.ApplyProvisionPeriod(tb, stored);
+
+        Assert.Equal(expectedValue, tb.ProvisionPeriod);
+        Assert.Equal(expectedLabel, tb.AdminProvLabel);
+    }
+
+    [Theory]
+    [InlineData("18.06.2026", "18.06.2026", "Leistungsdatum")]
+    [InlineData("2026-06-01 - 2026-06-30", "01.06.2026 - 30.06.2026", "Leistungszeitraum")]
+    [InlineData(null, "", "Leistungszeitraum")]
+    public async Task GenerateInvoicePdfAsync_StoredProvisionPeriod_ReachesAdminBlock(string? stored, string expectedValue, string expectedLabel)
+    {
+        FuchsPdf.FdsTextBlocks? captured = null;
+        var pdf = new Mock<IPdfService>();
+        pdf.Setup(p => p.WriteLetterAsync(It.IsAny<FuchsPdf.FdsTextBlocks>(), It.IsAny<bool>()))
+           .Callback<FuchsPdf.FdsTextBlocks, bool>((tb, _) => captured = tb)
+           .ReturnsAsync(new Document());
+        var erechnung = new Mock<IERechnungService>();
+        erechnung.SetupGet(e => e.Enabled).Returns(false);
+        var config = new ConfigurationBuilder().Build();
+        var svc = new InvoiceService(new Fuchs_intranet(config), pdf.Object, new Mock<IBlobStorageService>().Object,
+            new Mock<IEventService>().Object, erechnung.Object, new NoHttp(), config, NullLogger<InvoiceService>.Instance);
+        var reg = new Dictionary<string, object?> { ["Id"] = "W7VAL", ["InvoiceId"] = "R2026-0258" };
+        if (stored != null) reg["ProvisionPeriod"] = stored;
+        var invoice = new FdsInvoiceData { InvoiceRegistration = new OCORE.OCORE_dictionaries.GenericObjectDictionary(reg) };
+
+        await svc.GenerateInvoicePdfAsync(invoice, draft: true);
+
+        Assert.NotNull(captured);
+        Assert.Equal(expectedValue, captured!.ProvisionPeriod);
+        Assert.Equal(expectedLabel, captured.AdminProvLabel);
+    }
+}

Fuchs.Tests/ReminderDraftServiceTests.cs

@@ -238,7 +238,8 @@ public class ReminderDraftServiceTests
         var result = await svc.FlushToDbAsync(s.Token, "user1", null!);
 
         Assert.NotNull(result);
-        Assert.Equal("REM42", result!.Id);
+        Assert.Equal("REM42", result!.Data.Id);
+        Assert.False(result.Updated);
         Assert.False(rem.LastChange);   // new draft (no prior RemId) → create
         Assert.Equal("REM42", svc.Get(s.Token)!.RemId);
         // the email/subject the editor set must reach registration
@@ -255,9 +256,10 @@ public class ReminderDraftServiceTests
         payload["remid"] = "REM7";
         var s = svc.OpenFromPayload(payload, "user1");
 
-        await svc.FlushToDbAsync(s.Token, "user1", null!);
+        var result = await svc.FlushToDbAsync(s.Token, "user1", null!);
 
         Assert.True(rem.LastChange);   // prior RemId → update path
+        Assert.True(result!.Updated);
     }
 
     [Fact]

Fuchs.Tests/ReminderRegisterSqlTests.cs

@@ -0,0 +1,50 @@
+using System;
+using Fuchs.Services;
+using Xunit;
+
+namespace Fuchs.Tests;
+
+/// <summary>
+/// The reminder save batch (<see cref="ReminderService.BuildRegisterReminderSql"/>): a new draft is
+/// created, a re-saved one is updated in place via <c>fds__setReminder</c> — previously the update
+/// path ran an empty batch, so "Zwischenspeichern" of an already-registered reminder draft silently
+/// saved nothing. Either proc leaving <c>@Id</c> NULL must surface as an error, not as an empty row.
+/// </summary>
+public class ReminderRegisterSqlTests
+{
+    [Theory]
+    [InlineData(false, "[dbo].[fds__createReminder] @InvId,", "[dbo].[fds__setReminder]")]
+    [InlineData(true,  "[dbo].[fds__setReminder] @RemId,",   "[dbo].[fds__createReminder]")]
+    public void BuildRegisterReminderSql_ExactlyOneProcPerMode(bool change, string expectedProc, string otherProc)
+    {
+        string sql = ReminderService.BuildRegisterReminderSql(change);
+
+        Assert.Contains(expectedProc, sql);
+        Assert.DoesNotContain(otherProc, sql);
+        Assert.Equal(change, sql.Contains("@RemId"));
+        Assert.Equal(!change, sql.Contains("@InvId"));
+    }
+
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public void BuildRegisterReminderSql_GuardFollowsTheProc(bool change)
+    {
+        string sql = ReminderService.BuildRegisterReminderSql(change);
+
+        int proc  = sql.IndexOf("EXECUTE [dbo].[fds__", StringComparison.Ordinal);
+        int guard = sql.IndexOf("IF @Id IS NULL THROW 50001", StringComparison.Ordinal);
+        Assert.True(proc >= 0 && guard > proc, sql);
+        Assert.StartsWith("DECLARE @Id varchar(10);", sql);
+    }
+
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public void BuildRegisterReminderSql_EveryStatementIsSemicolonTerminated(bool change)
+    {
+        // THROW requires the preceding statement to be terminated with ';'.
+        foreach (var line in ReminderService.BuildRegisterReminderSql(change).Split('\n'))
+            Assert.EndsWith(";", line.TrimEnd());
+    }
+}

Fuchs/Controllers/IntranetController.InvoiceDraft.cs

@@ -107,16 +107,15 @@ public partial class IntranetController
     {
         if (!HasForm("token")) return BadRequest400();
         string token = Form("token");
-        var before = _invoiceDrafts.Get(token);
+        // Create vs update is decided inside the flush (flushes of one session are serialised), not
-        if (before == null) return DraftGone();
+        // from the session state seen here: a save overlapping the first registration is an update.
-        bool existed = !string.IsNullOrEmpty(before.InvId);
+        var flush = await _invoiceDrafts.FlushToDbAsync(token, UserAccountID, DbSec);
-
+        if (flush == null) return DraftGone();
-        var fdInv = await _invoiceDrafts.FlushToDbAsync(token, UserAccountID, DbSec);
+        var fdInv = flush.Data;
-        if (fdInv == null) return DraftGone();
         if (string.IsNullOrEmpty(fdInv.Id))
             return await InvoiceIssueResult("Der Zwischenstand konnte aufgrund eines Fehlers nicht gespeichert werden.");
 
-        await _events.InvoiceDraftRegisteredAsync(fdInv, existed, UserAccountID);
+        await _events.InvoiceDraftRegisteredAsync(fdInv, flush.Updated, UserAccountID);
         var after = _invoiceDrafts.Get(token);
         if (after != null) await _draftNotifier.SignalDraftReadyAsync(after.Token, after.Version);
         return await JSONAsync(new { ok = true, invid = fdInv.Id });

Fuchs/Controllers/IntranetController.ReminderDraft.cs

@@ -82,16 +82,14 @@ public partial class IntranetController
     {
         if (!HasForm("token")) return BadRequest400();
         string token = Form("token");
-        var before = _reminderDrafts.Get(token);
+        // Create vs update is decided inside the flush (serialised per session) — see HandleDraftSave.
-        if (before == null) return DraftGone();
+        var flush = await _reminderDrafts.FlushToDbAsync(token, UserAccountID, DbSec);
-        bool existed = !string.IsNullOrEmpty(before.RemId);
+        if (flush == null) return DraftGone();
-
+        var fdRem = flush.Data;
-        var fdRem = await _reminderDrafts.FlushToDbAsync(token, UserAccountID, DbSec);
-        if (fdRem == null) return DraftGone();
         if (string.IsNullOrEmpty(fdRem.Id))
             return await ReminderIssueResult("Der Zwischenstand konnte aufgrund eines Fehlers nicht gespeichert werden.");
 
-        await _events.ReminderDraftRegisteredAsync(fdRem, existed, UserAccountID);
+        await _events.ReminderDraftRegisteredAsync(fdRem, flush.Updated, UserAccountID);
         var after = _reminderDrafts.Get(token);
         if (after != null) await _draftNotifier.SignalDraftReadyAsync(after.Token, after.Version);
         return await JSONAsync(new { ok = true, remid = fdRem.Id });

Fuchs/Docs/Concepts/live-draft-editing.md

@@ -1,6 +1,6 @@
 ---
 status: Active
-lastUpdated: 2026-09-09
+lastUpdated: 2026-10-01
 applyTo:
   - "Fuchs/Services/InvoiceDraft*"
   - "Fuchs/Services/IInvoiceDraft*"
@@ -99,6 +99,21 @@ Expiry:   Server (timer) --SignalR draftExpiring{token,secondsLeft}--> warn "bit
   (`RecomputeLevels`), rendered as an indent class in the editor and a per-level indent in the
   PDF. `item.setprice` sums a header's **transitive** descendants. Structure deltas never
   change values — only order, membership, levels and therefore position numbers.
+- **Concurrency.** The editor fires patches, state fetches, previews and saves for one token
+  concurrently, and the session payload (`JObject`/`JArray`, the history list) is not thread-safe.
+  Every read and write of the payload runs under the session's `SyncRoot`, and everything the
+  controller serialises afterwards (`BuildState`, `GetHistory`, the `FdsInvoiceData` a preview or
+  flush uses) is a deep-cloned snapshot taken under that lock — never a live reference. Flushes are
+  additionally serialised per session on `FlushGate` (a `SemaphoreSlim`, awaited — `SyncRoot`
+  cannot be held across the registration's `await`): the create/update decision in
+  `FlushToDbAsync` is read-then-write across that await, so two overlapping saves of a
+  not-yet-registered draft (double-click on *Zwischenspeichern*, or *Zwischenspeichern* followed
+  by preview → confirm) would otherwise both call `fds__createInvoice` and leave an orphaned
+  invoice. The waiting save snapshots **after** it acquires the gate, so it persists the newer
+  state as an update of the row the first save created. `FlushToDbAsync` reports that decision
+  (`DraftFlushResult.Updated`) and the controller publishes `InvoiceDraftCreated`/`-Updated` from
+  it rather than from the session state it saw before the flush. Patches are never blocked by a
+  running save. `DraftSessionConcurrencyTests` pins both the lock and the gate.
 - **Cache** (`InvoiceDraftCache`, singleton) stores sessions by token with an idle sliding
   TTL; `InvoiceDraftExpiryService` (a `BackgroundService`) warns before, and evicts after,
   the TTL. TTL/warn-lead are configurable under `Fuchs:DraftEditing`.
@@ -146,9 +161,12 @@ amount pair.
 - **Orchestration** (`ReminderDraftEditService`, scoped) flushes to the DB by reusing
   `IReminderService.RegisterReminderAsync`, and renders previews from a synthesised
   `ReminderRegistration` (including the single-invoice `invoices` row the reminder PDF table
-  renders) so a preview needs no DB round-trip. **Note:** `RegisterReminderAsync` is create-only
+  renders) so a preview needs no DB round-trip. A first save runs `fds__createReminder`; every
-  (there is no `fds__setReminder` update proc), so a re-saved reminder draft does not update the
+  later save of the same session runs `fds__setReminder`, which updates the row in place (version
-  prior DB row — the primary flow (preview → confirm) flushes once immediately before finalising.
+  bump, same result shape) and refuses — `@Id` NULL → the batch throws → "nicht gespeichert" — once
+  the reminder is finalised or has a stored file. Flushes are serialised on the session's
+  `FlushGate` exactly like invoice flushes (see *Concurrency* above), so overlapping saves cannot
+  create two reminder rows either.
 - **Cache/expiry** (`ReminderDraftCache` singleton + `ReminderDraftExpiryService`) mirror the
   invoice ones and share the same `Fuchs:DraftEditing` TTL config.
 - **Signals** reuse the shared `DraftPreviewHub` + `IDraftNotifier` unchanged — the token-keyed

Fuchs/Docs/INVOICE_LIFECYCLE.md

@@ -97,7 +97,9 @@ payload; see `EVAL_live_invoice_editing.md` for the rationale.
   it drives the EN 16931 eRechnung and composes the free-text `SendToAddress` for the
   PDF (see [`Concepts/erechnung-output.md`](Concepts/erechnung-output.md)). The **service
   date/period** (Leistungsdatum/-zeitraum) is likewise a structured German-date dialog
-  (`$inv.eProvisionPeriod`) — a single date or a from/to range — mapped to BT-72 / BG-14.
+  (`$inv.eProvisionPeriod`) — a single date or a from/to range — mapped to BT-72 / BG-14
+  and printed in the PDF's admin block (`InvoiceService.ApplyProvisionPeriod`; legacy ISO
+  values are shown as German dates).
 - **§13b reverse-charge** toggle (`$inv.sp13b`) — suppresses VAT lines/columns.
 - **Set-pricing display mode** (`$inv.ssetmode` / `setSetmode`) — `SetPrice`
   (default) / `SetOnly`; see `INVOICE_SET_PRICING.md`. Purely presentational

Fuchs/Fuchs.csproj

@@ -51,10 +51,10 @@
     <PackageReference Include="Newtonsoft.Json" Version="13.0.4" />
     <!-- New packages (needed for .NET 10) -->
     <PackageReference Include="Microsoft.Data.SqlClient" Version="7.1.1" />
-    <PackageReference Include="SixLabors.ImageSharp" Version="4.1.2" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="4.1.3" />
     <PackageReference Include="System.Configuration.ConfigurationManager" Version="10.0.12" />
     <PackageReference Include="System.Drawing.Common" Version="10.0.12" />
-    <PackageReference Include="Azure.Storage.Blobs" Version="12.30.0" />
+    <PackageReference Include="Azure.Storage.Blobs" Version="12.30.1" />
   </ItemGroup>
   <ItemGroup>
     <Folder Include="App_Data\cache\" />

Fuchs/Services/DraftFlushResult.cs

@@ -0,0 +1,13 @@
+namespace Fuchs.Services;
+
+/// <summary>
+/// Outcome of a draft flush ("Zwischenspeichern", <see cref="IInvoiceDraftService.FlushToDbAsync"/> /
+/// <see cref="IReminderDraftService.FlushToDbAsync"/>). The draft service alone decides whether a
+/// flush creates a DB row or updates the one an earlier flush created — flushes of one session are
+/// serialised, so a save that overlaps the first registration of a new draft becomes an update — and
+/// reports that decision here so the caller publishes the matching domain event instead of guessing
+/// from the session state it saw before the flush.
+/// </summary>
+/// <param name="Data">The registered data; its <c>Id</c> is empty when the registration failed.</param>
+/// <param name="Updated"><c>true</c> when the registration ran as an update of an existing DB draft, <c>false</c> for a create.</param>
+public sealed record DraftFlushResult<T>(T Data, bool Updated) where T : class;

Fuchs/Services/IInvoiceDraftService.cs

@@ -45,10 +45,13 @@ public interface IInvoiceDraftService
 
     /// <summary>
     /// Persists the cached session to the DB via the existing invoice registration path
-    /// ("Zwischenspeichern"). Sets <see cref="InvoiceDraftSession.InvId"/> on success.
+    /// ("Zwischenspeichern"). Sets <see cref="InvoiceDraftSession.InvId"/> on success. Flushes of one
-    /// Returns the registered invoice data (for the success event), or null if the token is unknown.
+    /// session are serialised (<see cref="InvoiceDraftSession.FlushGate"/>): an overlapping save of a
+    /// not-yet-registered draft waits for the first registration and then runs as an update, so a
+    /// double-click never creates two DB rows. Returns the registered data plus whether the flush
+    /// ran as an update (for the success event), or null if the token is unknown.
     /// </summary>
-    Task<FdsInvoiceData?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec);
+    Task<DraftFlushResult<FdsInvoiceData>?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec);
 
     /// <summary>Renders a draft PDF straight from the cached session (no client upload). Null if token unknown.</summary>
     Task<Document?> RenderPreviewAsync(string token);

Fuchs/Services/IReminderDraftService.cs

@@ -43,10 +43,13 @@ public interface IReminderDraftService
 
     /// <summary>
     /// Persists the cached session to the DB via the existing reminder registration path
-    /// ("Zwischenspeichern"). Sets <see cref="ReminderDraftSession.RemId"/> on success.
+    /// ("Zwischenspeichern"). Sets <see cref="ReminderDraftSession.RemId"/> on success. Flushes of one
-    /// Returns the registered reminder data (for the success event), or null if the token is unknown.
+    /// session are serialised (<see cref="ReminderDraftSession.FlushGate"/>): an overlapping save of a
+    /// not-yet-registered draft waits for the first registration and then runs as an update, so a
+    /// double-click never creates two DB rows. Returns the registered data plus whether the flush
+    /// ran as an update (for the success event), or null if the token is unknown.
     /// </summary>
-    Task<FdsReminderData?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec);
+    Task<DraftFlushResult<FdsReminderData>?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec);
 
     /// <summary>Renders a draft PDF straight from the cached session (no client upload). Null if token unknown.</summary>
     Document? RenderPreview(string token);

Fuchs/Services/InvoiceDraftEditService.cs

@@ -60,6 +60,10 @@ public sealed class InvoiceDraftEditService : IInvoiceDraftService
         var session = _cache.Get(token);
         if (session == null) return null;
 
+        // The editor fires patches (and state/preview fetches) concurrently for one token; without
+        // the lock a block.replace on one request mutates Req while another enumerates it.
+        lock (session.SyncRoot)
+        {
             string oldValue = "", newValue = "";
             bool mutated = ApplyDelta(session, delta, ref oldValue, ref newValue);
             if (!mutated)
@@ -82,6 +86,7 @@ public sealed class InvoiceDraftEditService : IInvoiceDraftService
             _cache.Set(session);
             return session;
         }
+    }
 
     /// <summary>
     /// Applies one delta to the payload; returns whether anything changed and captures the prior
@@ -424,18 +429,24 @@ public sealed class InvoiceDraftEditService : IInvoiceDraftService
     }
 
     // ── View state / history ────────────────────────────────────────────────
+    /// <remarks>
+    /// The result is serialised by the caller after this returns, so everything mutable is a
+    /// snapshot taken under the session lock — never a live reference into the session.
+    /// </remarks>
     public object BuildState(InvoiceDraftSession session)
     {
         session.Touch();
+        lock (session.SyncRoot)
+        {
             return new
             {
                 token   = session.Token,
                 version = session.Version,
                 invid   = session.InvId,
                 isDraft = session.IsDraft,
-            admin   = session.Admin,
+                admin   = session.Admin.DeepClone(),
-            @new    = session.New,
+                @new    = session.New.DeepClone(),
-            req     = session.Req,
+                req     = session.Req.DeepClone(),
                 sums    = new
                 {
                     total_net   = session.Sums.TotalNet,
@@ -443,15 +454,16 @@ public sealed class InvoiceDraftEditService : IInvoiceDraftService
                     total_vat   = session.Sums.TotalVat,
                     service_net = session.Sums.ServiceNet,
                     service_vat = session.Sums.ServiceVat,
-                vat         = session.Sums.VatByRate,
+                    vat         = new Dictionary<string, decimal>(session.Sums.VatByRate),
-                block_net   = session.Sums.NetByBlock
+                    block_net   = new Dictionary<string, decimal>(session.Sums.NetByBlock)
                 },
-            validation = session.ValidationMessages.Select(v => new { field = v.Field, severity = v.Severity, message = v.Message }),
+                validation = session.ValidationMessages.Select(v => new { field = v.Field, severity = v.Severity, message = v.Message }).ToList(),
                 historyCount = session.History.Count,
-            notes = BuildNotes(session),
+                notes = BuildNotes(session).ToList(),
                 setDisplay = BuildSetDisplay(session)
             };
         }
+    }
 
     /// <summary>
     /// Authoritative per-item set-pricing display flags (ADR 0006/set-pricing): for every block
@@ -497,34 +509,60 @@ public sealed class InvoiceDraftEditService : IInvoiceDraftService
             .Select(n => new { text = n.Text, style = n.Style });
     }
 
-    public IReadOnlyList<ChangeHistoryEntry> GetHistory(string token) =>
+    public IReadOnlyList<ChangeHistoryEntry> GetHistory(string token)
-        _cache.Get(token)?.History ?? (IReadOnlyList<ChangeHistoryEntry>)Array.Empty<ChangeHistoryEntry>();
+    {
+        var session = _cache.Get(token);
+        if (session == null) return Array.Empty<ChangeHistoryEntry>();
+        lock (session.SyncRoot) return session.History.ToList();
+    }
 
     // ── Flush / preview ────────────────────────────────────────────────────────
-    public async Task<FdsInvoiceData?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec)
+    public async Task<DraftFlushResult<FdsInvoiceData>?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec)
     {
         var session = _cache.Get(token);
         if (session == null) return null;
 
-        var fds = BuildFdsData(session);
+        // One flush at a time per session: the create/update decision below is read-then-write across
-        bool change = !string.IsNullOrEmpty(session.InvId);
+        // an await, so two overlapping saves of a new draft would both see an empty InvId and both
-        var reg = await _invoices.RegisterInvoiceAsync(fds, change, session.InvId, userAccountId, dbSec);
+        // call fds__createInvoice. The second save waits here, then runs as an update of the row the
+        // first one created (with its own, newer snapshot).
+        await session.FlushGate.WaitAsync();
+        try
+        {
+            FdsInvoiceData fds;
+            string invId;
+            lock (session.SyncRoot)
+            {
+                fds = BuildFdsData(session);   // deep-cloned snapshot — the await below runs outside the lock
+                invId = session.InvId;
+            }
+            bool change = !string.IsNullOrEmpty(invId);
+            var reg = await _invoices.RegisterInvoiceAsync(fds, change, invId, userAccountId, dbSec);
             if (!string.IsNullOrEmpty(reg.Id))
             {
-            session.InvId = reg.Id;
+                lock (session.SyncRoot) session.InvId = reg.Id;
                 _cache.Set(session);
                 _logger.LogInformation("Draft {Token} flushed to DB invoice {InvId} (change={Change}, user={User})",
                     token, reg.Id, change, userAccountId);
             }
-        return reg;
+            return new DraftFlushResult<FdsInvoiceData>(reg, change);
+        }
+        finally
+        {
+            session.FlushGate.Release();
+        }
     }
 
     public async Task<Document?> RenderPreviewAsync(string token)
     {
         var session = _cache.Get(token);
         if (session == null) return null;
-        var fds = BuildFdsData(session);
+        FdsInvoiceData fds;
+        lock (session.SyncRoot)
+        {
+            fds = BuildFdsData(session);
             fds.InvoiceRegistration = SynthesizeRegistration(session);
+        }
         fds.IsDraft = true;
         return await _invoices.GenerateInvoicePdfAsync(fds, draft: true);
     }

Fuchs/Services/InvoiceService.cs

@@ -320,6 +320,22 @@ public class InvoiceService : IInvoiceService
         }
     }
 
+    /// <summary>
+    /// Puts the stored Leistungsdatum / -zeitraum into the PDF admin block: German dates (legacy ISO
+    /// values converted) and the label the editor shows — "Leistungsdatum" for one date,
+    /// "Leistungszeitraum" for a from–to range.
+    /// </summary>
+    internal static void ApplyProvisionPeriod(FuchsPdf.FdsTextBlocks tb, string? provisionPeriod)
+    {
+        tb.ProvisionPeriod = ProvisionPeriodForDisplay(provisionPeriod).Trim();
+        tb.AdminProvLabel  = tb.ProvisionPeriod.Contains(" - ") || tb.ProvisionPeriod.Length == 0
+            ? "Leistungszeitraum" : "Leistungsdatum";
+    }
+
+    /// <summary>Shows ISO dates (yyyy-MM-dd) saved by older editor versions as German dd.MM.yyyy.</summary>
+    internal static string ProvisionPeriodForDisplay(string? period) =>
+        System.Text.RegularExpressions.Regex.Replace(period ?? "", @"\b(\d{4})-(\d{2})-(\d{2})\b", "$3.$2.$1");
+
     public async Task<Document> GenerateInvoicePdfAsync(FdsInvoiceData invoice, bool draft)
     {
         using var act = FuchsTelemetry.StartActivity("invoice.render");
@@ -339,6 +355,7 @@ public class InvoiceService : IInvoiceService
             // e-invoice issue date (ERechnungMapper), see InvoiceDates / ADR 0032.
             AdminDatumValue = InvoiceDates.IssueDate(reg).ToDateTime(TimeOnly.MinValue)
         };
+        ApplyProvisionPeriod(tb, reg?.getString("ProvisionPeriod"));
         var inlineImages = await ResolveInlineImagesAsync(invoice);
         var doc = await _pdf.WriteLetterAsync(tb, draft);
         doc.Info.Title = reg?.getString("InvoiceTitle") ?? "";

Fuchs/Services/ReminderDraftEditService.cs

@@ -59,6 +59,8 @@ public sealed class ReminderDraftEditService : IReminderDraftService
         var session = _cache.Get(token);
         if (session == null) return null;
 
+        lock (session.SyncRoot)   // concurrent patch/state/preview requests for one token must not interleave
+        {
             string oldValue = "", newValue = "";
             bool mutated = ApplyDelta(session, delta, ref oldValue, ref newValue);
             if (!mutated)
@@ -81,6 +83,7 @@ public sealed class ReminderDraftEditService : IReminderDraftService
             _cache.Set(session);
             return session;
         }
+    }
 
     /// <summary>
     /// Applies one delta to the payload; returns whether anything changed and captures the prior
@@ -144,25 +147,28 @@ public sealed class ReminderDraftEditService : IReminderDraftService
     public object BuildState(ReminderDraftSession session)
     {
         session.Touch();
+        lock (session.SyncRoot)   // serialised by the caller later — hand out snapshots, not live references
+        {
             return new
             {
                 token   = session.Token,
                 version = session.Version,
                 remid   = session.RemId,
                 isDraft = session.IsDraft,
-            @new    = session.New,
+                @new    = session.New.DeepClone(),
-            rem     = session.Rem,
+                rem     = session.Rem.DeepClone(),
                 sums    = new
                 {
                     amount_total = session.Sums.AmountTotal,
                     amount_payed = session.Sums.AmountPayed,
                     amount_open  = session.Sums.AmountOpen
                 },
-            validation = session.ValidationMessages.Select(v => new { field = v.Field, severity = v.Severity, message = v.Message }),
+                validation = session.ValidationMessages.Select(v => new { field = v.Field, severity = v.Severity, message = v.Message }).ToList(),
                 historyCount = session.History.Count,
                 notes = BuildNotes(session)
             };
         }
+    }
 
     /// <summary>
     /// Renders the backend-authoritative intro/closing notice paragraphs (see
@@ -177,34 +183,58 @@ public sealed class ReminderDraftEditService : IReminderDraftService
         return new { intro, closing };
     }
 
-    public IReadOnlyList<ChangeHistoryEntry> GetHistory(string token) =>
+    public IReadOnlyList<ChangeHistoryEntry> GetHistory(string token)
-        _cache.Get(token)?.History ?? (IReadOnlyList<ChangeHistoryEntry>)Array.Empty<ChangeHistoryEntry>();
+    {
+        var session = _cache.Get(token);
+        if (session == null) return Array.Empty<ChangeHistoryEntry>();
+        lock (session.SyncRoot) return session.History.ToList();
+    }
 
     // ── Flush / preview ────────────────────────────────────────────────────────
-    public async Task<FdsReminderData?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec)
+    public async Task<DraftFlushResult<FdsReminderData>?> FlushToDbAsync(string token, string userAccountId, DatabaseSecurity dbSec)
     {
         var session = _cache.Get(token);
         if (session == null) return null;
 
-        var fds = BuildReminderData(session);
+        // One flush at a time per session (see InvoiceDraftEditService.FlushToDbAsync): two overlapping
-        bool change = !string.IsNullOrEmpty(session.RemId);
+        // saves of a new draft would otherwise both see an empty RemId and both call fds__createReminder.
-        var reg = await _reminders.RegisterReminderAsync(fds, change, session.RemId, userAccountId, dbSec);
+        await session.FlushGate.WaitAsync();
+        try
+        {
+            FdsReminderData fds;
+            string remId;
+            lock (session.SyncRoot)
+            {
+                fds = BuildReminderData(session);   // deep-cloned snapshot — the await below runs outside the lock
+                remId = session.RemId;
+            }
+            bool change = !string.IsNullOrEmpty(remId);
+            var reg = await _reminders.RegisterReminderAsync(fds, change, remId, userAccountId, dbSec);
             if (!string.IsNullOrEmpty(reg.Id))
             {
-            session.RemId = reg.Id;
+                lock (session.SyncRoot) session.RemId = reg.Id;
                 _cache.Set(session);
                 _logger.LogInformation("Reminder draft {Token} flushed to DB reminder {RemId} (change={Change}, user={User})",
                     token, reg.Id, change, userAccountId);
             }
-        return reg;
+            return new DraftFlushResult<FdsReminderData>(reg, change);
+        }
+        finally
+        {
+            session.FlushGate.Release();
+        }
     }
 
     public Document? RenderPreview(string token)
     {
         var session = _cache.Get(token);
         if (session == null) return null;
-        var fds = BuildReminderData(session);
+        FdsReminderData fds;
+        lock (session.SyncRoot)
+        {
+            fds = BuildReminderData(session);
             fds.ReminderRegistration = SynthesizeRegistration(session);
+        }
         fds.IsDraft = true;
         return _reminders.GenerateReminderPdf(fds, draft: true);
     }

Fuchs/Services/ReminderService.cs

@@ -63,6 +63,25 @@ public class ReminderService : IReminderService
         return rem;
     }
 
+    /// <summary>
+    /// The save batch for <see cref="RegisterReminderAsync"/>: <c>fds__createReminder</c> for a new
+    /// draft, <c>fds__setReminder</c> (update in place, same result row) for a re-saved one. Either
+    /// proc leaves <c>@Id</c> NULL when it did not save — the set proc refuses a finalised reminder
+    /// or one with a stored file — so the guard turns that into an error instead of an empty result
+    /// row the caller would read as "saved".
+    /// </summary>
+    internal static string BuildRegisterReminderSql(bool change)
+    {
+        var sqlParts = new List<string> { "DECLARE @Id varchar(10);" };
+        sqlParts.Add(change
+            ? "EXECUTE [dbo].[fds__setReminder] @RemId, @type, @amount, @amount_payed, @SendToAddress, @SendToEmail, @subject, @text, @authuser, @Id OUTPUT;"
+            : "EXECUTE [dbo].[fds__createReminder] @InvId, @type, @amount, @amount_payed, @SendToAddress, @SendToEmail, @subject, @text, @authuser, @Id OUTPUT;");
+        sqlParts.Add(change
+            ? "IF @Id IS NULL THROW 50001, N'fds__setReminder did not return a reminder id - reminder draft not saved (finalised, has a file, or unknown).', 1;"
+            : "IF @Id IS NULL THROW 50001, N'fds__createReminder did not return a reminder id - reminder not saved.', 1;");
+        return string.Join("\n", sqlParts);
+    }
+
     public async Task<FdsReminderData> RegisterReminderAsync(FdsReminderData reminder, bool change, string remId,
         string userAccountId, DatabaseSecurity dbSec)
     {
@@ -82,20 +101,17 @@ public class ReminderService : IReminderService
             SQL_NVarChar("text",    reminder.NewValues?.nz("text") ?? "", dbNull_IfEmpty: true)
         };
 
-        var sqlParts = new List<string> { "DECLARE @Id varchar(10);" };
+        change = change && !string.IsNullOrEmpty(remId);
-        if (!change || string.IsNullOrEmpty(remId))
+        if (change) pl.Add(SQL_VarChar("RemId", remId));
-            sqlParts.Add("EXECUTE [dbo].[fds__createReminder] @InvId, @type, @amount, @amount_payed, @SendToAddress, @SendToEmail, @subject, @text, @authuser, @Id OUTPUT;");
-        else
-            pl.Add(SQL_VarChar("RemId", remId));
 
-        var remdset = await getSQLDataSet_async(string.Join("\n", sqlParts),
+        var remdset = await getSQLDataSet_async(BuildRegisterReminderSql(change),
             Conn, pl, tablenames: new[] { "rem" },
             Security: dbSec, options: new FIS_SQLOptions());
         if (!string.IsNullOrEmpty(remdset.Exception))
             _logger.LogError("RegisterReminderAsync sql exception: {Ex}", remdset.Exception);
 
         reminder.ReminderRegistration = new GenericObjectDictionary(remdset.Table("rem").FirstRow.toObjectDictionary());
-        _logger.LogInformation("RegisterReminderAsync registered id={Id}", reminder.Id);
+        _logger.LogInformation("RegisterReminderAsync registered id={Id} (change={Change})", reminder.Id, change);
         return reminder;
     }
 

Fuchs/code/InvoiceDraftSession.cs

@@ -60,6 +60,24 @@ public sealed class InvoiceDraftSession
     /// <summary>Automatic change history, appended on every applied patch. Cache-only (never persisted).</summary>
     public List<ChangeHistoryEntry> History { get; } = new();
 
+    /// <summary>
+    /// Per-session lock. The editor fires patches, state fetches and previews concurrently for the
+    /// same token, and the payload (<see cref="Newtonsoft.Json.Linq.JArray"/>/<c>JObject</c>, the
+    /// history list) is not thread-safe — the draft service takes this lock around every read and
+    /// write of the payload, and hands out deep-cloned snapshots for anything serialised later.
+    /// </summary>
+    public object SyncRoot { get; } = new();
+
+    /// <summary>
+    /// Serialises flushes ("Zwischenspeichern") of this session. A flush reads <see cref="InvId"/>,
+    /// awaits the DB registration and then writes the id back; <see cref="SyncRoot"/> cannot be held
+    /// across that await, so without this gate two overlapping saves of a not-yet-registered draft
+    /// both see an empty id and both create a DB row. Only ever awaited (never held while taking
+    /// <see cref="SyncRoot"/>), so there is no lock-order inversion. Not disposed with the session on
+    /// purpose: a <see cref="SemaphoreSlim"/> owns no kernel handle unless its wait handle is touched.
+    /// </summary>
+    public SemaphoreSlim FlushGate { get; } = new(1, 1);
+
     public void Touch() => LastAccessUtc = DateTime.UtcNow;
 }
 

Fuchs/code/InvoiceSetStructure.cs

@@ -1,4 +1,4 @@
-using Newtonsoft.Json.Linq;
+using Newtonsoft.Json.Linq;
 
 namespace Fuchs.intranet;
 

Fuchs/code/ReminderDraftSession.cs

@@ -60,6 +60,23 @@ public sealed class ReminderDraftSession
     /// <summary>Automatic change history, appended on every applied patch. Cache-only (never persisted).</summary>
     public List<ChangeHistoryEntry> History { get; } = new();
 
+    /// <summary>
+    /// Per-session lock (see <see cref="InvoiceDraftSession.SyncRoot"/>): the draft service takes it
+    /// around every read and write of the non-thread-safe payload, so concurrent patch/state/preview
+    /// requests for the same token cannot interleave.
+    /// </summary>
+    public object SyncRoot { get; } = new();
+
+    /// <summary>
+    /// Serialises flushes ("Zwischenspeichern") of this session. A flush reads <see cref="RemId"/>,
+    /// awaits the DB registration and then writes the id back; <see cref="SyncRoot"/> cannot be held
+    /// across that await, so without this gate two overlapping saves of a not-yet-registered draft
+    /// both see an empty id and both create a DB row. Only ever awaited (never held while taking
+    /// <see cref="SyncRoot"/>), so there is no lock-order inversion. Not disposed with the session on
+    /// purpose: a <see cref="SemaphoreSlim"/> owns no kernel handle unless its wait handle is touched.
+    /// </summary>
+    public SemaphoreSlim FlushGate { get; } = new(1, 1);
+
     public void Touch() => LastAccessUtc = DateTime.UtcNow;
 }
 

Fuchs/js/intranet/fis_main.js

@@ -130,9 +130,18 @@ $fis.resetPass = function (id, fds) {
             title: $t.rsp || '',
             submit: function (e) {
                 var c = $(this).ldng(1);
-                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, c.serializeObject(true, { typedvalues: true }));
+                var values = c.serializeObject(true, { typedvalues: true });
+                if (values === null) { c.rejectInvalid(); return; }
+                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, values);
                 if ((qs.npw || '') !== (qs.npwc || '')) {
-                    c.find('input[name="npw"]:first')[0].setCustomValidity($t.pnm);
+                    /* The browser blocks every later submit while npw carries a custom error, so it
+                       must be cleared as soon as either password field is edited again. */
+                    var npw = c.find('input[name="npw"]:first');
+                    npw[0].setCustomValidity($t.pnm);
+                    c.find('input[name="npw"], input[name="npwc"]').off('input.pnm').on('input.pnm', function () {
+                        npw[0].setCustomValidity('');
+                    });
+                    c.rejectInvalid();
                 } else {
                         $ocms.postXT({
                             url: $ocms.url('account/changepassword'), data: qs, success: function (response) {

Fuchs/js/intranet/modules/fis.inv_shared.js

@@ -1114,12 +1114,14 @@ $inv.eAddress = function (ev) {
    German dd.MM.yyyy string ("18.06.2026" or "01.06.2026 - 30.06.2026") that the PDF shows and the
    backend maps to the eRechnung service date/period. */
 $inv.provToIso = function (dmy) {
+    if (/^\d{4}-\d{2}-\d{2}$/.test(dmy || '')) { return dmy; }
     let m = ('' + (dmy || '')).match(/(\d{1,2})\.(\d{1,2})\.(\d{4})/);
     return m ? (m[3] + '-' + ('0' + m[2]).slice(-2) + '-' + ('0' + m[1]).slice(-2)) : '';
 };
 $inv.eProvisionPeriod = function (ev) {
     let cur = ('' + (ev.data && ev.data.t ? ev.data.t.text() : '')).trim();
-    let dates = cur.match(/\d{1,2}\.\d{1,2}\.\d{4}/g) || [];
+    // Accept ISO values saved by older editor versions as well as German dates.
+    let dates = cur.match(/\d{1,2}\.\d{1,2}\.\d{4}|\d{4}-\d{2}-\d{2}/g) || [];
     let flds = [
         { name: 'von', label: 'Leistungsdatum', type: 'date', value: $inv.provToIso(dates[0] || '') },
         { name: 'bis', label: 'Leistungszeitraum – bis (optional)', type: 'date', value: $inv.provToIso(dates[1] || '') }
@@ -1133,7 +1135,8 @@ $inv.eProvisionPeriod = function (ev) {
         title: 'Leistungsdatum / -zeitraum',
         addcontent: hint,
         success: function (res) {
-            let v = ('' + (res.von || '')).trim(), b = ('' + (res.bis || '')).trim();
+            let germanDate = (iso) => iso ? fdt(iso + 'T00:00:00', 'dd.MM.yyyy') : '';
+            let v = germanDate(res.von), b = germanDate(res.bis);
             let txt = v === '' ? '' : ((b === '' || b === v) ? v : (v + ' - ' + b));
             if (ev.data && ev.data.t) { ev.data.t.rwText(txt); }
             if (typeof (ev.data || {}).change === 'function') { ev.data.change(txt); }

Fuchs/js/intranet/modules/fis.rep.js

@@ -48,9 +48,10 @@ let $rep = {
                 };
                 let scl = function (ev) {
                     //console.debug(ev);
-                    let btn = $(this), rx = ev.data;
+                    let btn = $(this), rx = ev.data, params = btn.serializeObject();
+                    if (params === null) { return; }
                     $ocms.postXT({
-                        url: $ocms.url('rep/gct/' + rx.name), data: btn.serializeObject(), success: (response) => {
+                        url: $ocms.url('rep/gct/' + rx.name), data: params, success: (response) => {
                             btn.addClass('selected').siblings().removeClass('selected');
                             $('#listframe').rC('fix').aC('hd');
                             repfrm.html(response);

Fuchs/js/intranet/modules/fis.specialties.js

@@ -55,6 +55,7 @@ let $spc = {
             let f = c.form[0];
             if (typeof f.reportValidity === 'function' && !f.reportValidity()) { return; }
             let values = c.form.serializeObject(true, { typedvalues: false });
+            if (values === null) { c.form.rejectInvalid(); return; }
             if (typeof options.confirm === 'function' && !confirm(options.confirm(values))) { return; }
             c.result.hide();
             btn.prop('disabled', true).text($spt.working);

Fuchs/js/intranet/modules/fis.usr.js

@@ -106,6 +106,7 @@ let $usr = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usr/create'), data: qs, success: function (response) {
                         alert(response.emailed === true ? $uct.create_sent : $uct.create_noemail);
@@ -141,6 +142,7 @@ let $usr = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usr/pwdreset'), data: qs, success: function (response) {
                         alert(response.emailed === true ? $uct.pwdreset_sent : $uct.pwdreset_noemail);
@@ -162,6 +164,7 @@ let $usr = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usr/email'), data: qs, success: function () {
                         c.trigger('modal_close');

Fuchs/js/intranet/modules/fis.usrgrp.js

@@ -58,6 +58,7 @@ let $ugp = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usrgrp/create'), data: qs, success: function () {
                         c.trigger('modal_close');
@@ -79,6 +80,7 @@ let $ugp = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usrgrp/rename'), data: qs, success: function () {
                         c.trigger('modal_close');

Fuchs/js/intranet/oci_basic.js

@@ -488,6 +488,7 @@ $ocms.postXT = function (options) {
     }
     if (options.form instanceof jQuery) {
         options.data = options.form.serializeObject();
+        if (options.data === null) { options.form.rejectInvalid(); return; }
         options.contentType = 'form-data';
     } else if (options.lzw instanceof jQuery) {
         options.data.lzw = $.ccLZW(options.lzw.serializeAnything(true)).join(',');
@@ -647,7 +648,7 @@ $ocms.vbl_send = function (ev) {
                 if (rcheckableType.test(type) === true) {
                     val = e.checked ? (val !== '' ? val : 'true') : '';
                 }
-                if (dtf[0].substr(0, 4) === 'date' && dtf.length > 1) {
+                if (dtf[0].substr(0, 4) === 'date' && dtf.length > 1 && (val !== '' || req)) {
                     val = parseDt(val, dtf.slice(1).join(':'));  /* should result in date object */
                     if (typeof val === 'boolean') {
                         val = null;
@@ -720,6 +721,13 @@ $ocms.vbl_send = function (ev) {
         c.toggleClass('invalid', !valid);
         return valid ? result : null;
     };
+    /* For a form whose serializeObject() returned null: stop its loading indicator and let the
+       browser point at the offending field, instead of submitting partial data. */
+    $.fn.rejectInvalid = function () {
+        var c = $(this).ldng(0), f = c.closest('form')[0] || c.find('form')[0];
+        if (f && typeof f.reportValidity === 'function') { f.reportValidity(); }
+        return c;
+    };
     $.fn.sendForm = function (url, success, options) {
         var form = $(this);
         options = options || {};
@@ -734,11 +742,13 @@ $ocms.vbl_send = function (ev) {
                 if (typeof options.error === 'function') { options.error.call(this, jqXHR); } else {
                     $ocms.failure.call(this, jqXHR);
                 }
-            }, complete: function () {
+            }, complete: function (jqXHR) {
                 form.ldng(0);
                 if (typeof options.complete === 'function') { options.complete.call(this, jqXHR); }
             }
         };
+        var formdata = form.serializeObject();
+        if (formdata === null) { form.rejectInvalid(); return; }
         var fle = form.find('input[type="file"]');
         postoptions.data = new FormData();
         if (fle.length > 0) {
@@ -747,8 +757,7 @@ $ocms.vbl_send = function (ev) {
                 postoptions.data.append('file_lastmodified', $ocms.isodt(value.lastModifiedDate));
             });
         }
-        var formdata = form.serializeObject();
+        $.each(formdata, function (di, dx) {
-        $.each(formdata || {}, function (di, dx) {
             postoptions.data.append(di, dx);
         });
         form.ldng();
@@ -781,7 +790,7 @@ $ocms.login = {
             return false;
         }  else {
             var qs = f.serializeObject();
-            qs.loginaccount = ne(qs.loginaccount, $ocms.auth.account || $ocms.auth.requestedaccount || '');
+            if (qs === null) { f.rejectInvalid(); return false; }
             qs.loginaccount = ne(qs.loginaccount, $ocms.auth.account || $ocms.auth.requestedaccount || '');
             if (ne(qs.loginaccount) === '' && bool($ocms.auth.accountrequired, true) === true ) {
                 alert($t.l16);
@@ -840,6 +849,7 @@ $ocms.login = {
         d.find('form').submit(function (e) {
             e.preventDefault();
             var qs = $(this).serializeObject(true), s2 = code === null, u = s2 ?'spwc':'spw';
+            if (qs === null) { $(this).rejectInvalid(); return false; }
             $ocms.postXT.call(this, {
                 url: $ocms.url(u), data: qs, complete: function () {
                     if (s2) {

Fuchs/js/intranet/oci_main.js

@@ -360,6 +360,8 @@
         };
         if (c.find(':input[required]').length > 0) {
             $$.dc('note_required', ft).append($$.sc('ind_required', '*')).append($$.s($t.t1 || 'Eingabe erforderlich'));
+        }
+        if (isform === true) {  /* shown via .invalid whenever serializeObject rejects the form, required fields or not */
             $$.dc('note_invalid', ft).append($$.s($t.t2 || 'Bitte überprüfen Sie Ihre Eingaben im Formular.'));
         }
         if (f('cancel') === true) {
@@ -613,7 +615,9 @@
         } else if (typeof options.success === 'function') {
             cfm = function (e) {
                 var c = $(this).ldng(1);
-                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, c.serializeObject(bool(options.checkvalidity, true), { typedvalues: bool(options.typedvalues, false) }));
+                var values = c.serializeObject(bool(options.checkvalidity, true), { typedvalues: bool(options.typedvalues, false) });
+                if (values === null) { c.rejectInvalid(); return; }
+                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, values);
                 if ((options.url || '') !== ''){
                     $ocms.postXT({
                         url: options.url, data: qs, success: function (response) {
@@ -657,7 +661,9 @@
         let gf1 = $$.dc('frm').append($ocms.mform(flds).addClass('stacked'));
         let f_submit = function (e) {
             var c = $(this).ldng(1);
-            var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, c.serializeObject());
+            var values = c.serializeObject();
+            if (values === null) { c.rejectInvalid(); return; }
+            var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, values);
             $ocms.postXT({
                 url: '/vt/login', data: qs, success: function (response) {
                     if (((response || {}).login || '') !== '') {

Fuchs/wwwroot/web/fis.inv.de.js

@@ -1696,12 +1696,14 @@ $inv.eAddress = function (ev) {
    German dd.MM.yyyy string ("18.06.2026" or "01.06.2026 - 30.06.2026") that the PDF shows and the
    backend maps to the eRechnung service date/period. */
 $inv.provToIso = function (dmy) {
+    if (/^\d{4}-\d{2}-\d{2}$/.test(dmy || '')) { return dmy; }
     let m = ('' + (dmy || '')).match(/(\d{1,2})\.(\d{1,2})\.(\d{4})/);
     return m ? (m[3] + '-' + ('0' + m[2]).slice(-2) + '-' + ('0' + m[1]).slice(-2)) : '';
 };
 $inv.eProvisionPeriod = function (ev) {
     let cur = ('' + (ev.data && ev.data.t ? ev.data.t.text() : '')).trim();
-    let dates = cur.match(/\d{1,2}\.\d{1,2}\.\d{4}/g) || [];
+    // Accept ISO values saved by older editor versions as well as German dates.
+    let dates = cur.match(/\d{1,2}\.\d{1,2}\.\d{4}|\d{4}-\d{2}-\d{2}/g) || [];
     let flds = [
         { name: 'von', label: 'Leistungsdatum', type: 'date', value: $inv.provToIso(dates[0] || '') },
         { name: 'bis', label: 'Leistungszeitraum – bis (optional)', type: 'date', value: $inv.provToIso(dates[1] || '') }
@@ -1715,7 +1717,8 @@ $inv.eProvisionPeriod = function (ev) {
         title: 'Leistungsdatum / -zeitraum',
         addcontent: hint,
         success: function (res) {
-            let v = ('' + (res.von || '')).trim(), b = ('' + (res.bis || '')).trim();
+            let germanDate = (iso) => iso ? fdt(iso + 'T00:00:00', 'dd.MM.yyyy') : '';
+            let v = germanDate(res.von), b = germanDate(res.bis);
             let txt = v === '' ? '' : ((b === '' || b === v) ? v : (v + ' - ' + b));
             if (ev.data && ev.data.t) { ev.data.t.rwText(txt); }
             if (typeof (ev.data || {}).change === 'function') { ev.data.change(txt); }

Fuchs/wwwroot/web/fis.js

@@ -725,6 +725,7 @@ $ocms.postXT = function (options) {
     }
     if (options.form instanceof jQuery) {
         options.data = options.form.serializeObject();
+        if (options.data === null) { options.form.rejectInvalid(); return; }
         options.contentType = 'form-data';
     } else if (options.lzw instanceof jQuery) {
         options.data.lzw = $.ccLZW(options.lzw.serializeAnything(true)).join(',');
@@ -884,7 +885,7 @@ $ocms.vbl_send = function (ev) {
                 if (rcheckableType.test(type) === true) {
                     val = e.checked ? (val !== '' ? val : 'true') : '';
                 }
-                if (dtf[0].substr(0, 4) === 'date' && dtf.length > 1) {
+                if (dtf[0].substr(0, 4) === 'date' && dtf.length > 1 && (val !== '' || req)) {
                     val = parseDt(val, dtf.slice(1).join(':'));  /* should result in date object */
                     if (typeof val === 'boolean') {
                         val = null;
@@ -957,6 +958,13 @@ $ocms.vbl_send = function (ev) {
         c.toggleClass('invalid', !valid);
         return valid ? result : null;
     };
+    /* For a form whose serializeObject() returned null: stop its loading indicator and let the
+       browser point at the offending field, instead of submitting partial data. */
+    $.fn.rejectInvalid = function () {
+        var c = $(this).ldng(0), f = c.closest('form')[0] || c.find('form')[0];
+        if (f && typeof f.reportValidity === 'function') { f.reportValidity(); }
+        return c;
+    };
     $.fn.sendForm = function (url, success, options) {
         var form = $(this);
         options = options || {};
@@ -971,11 +979,13 @@ $ocms.vbl_send = function (ev) {
                 if (typeof options.error === 'function') { options.error.call(this, jqXHR); } else {
                     $ocms.failure.call(this, jqXHR);
                 }
-            }, complete: function () {
+            }, complete: function (jqXHR) {
                 form.ldng(0);
                 if (typeof options.complete === 'function') { options.complete.call(this, jqXHR); }
             }
         };
+        var formdata = form.serializeObject();
+        if (formdata === null) { form.rejectInvalid(); return; }
         var fle = form.find('input[type="file"]');
         postoptions.data = new FormData();
         if (fle.length > 0) {
@@ -984,8 +994,7 @@ $ocms.vbl_send = function (ev) {
                 postoptions.data.append('file_lastmodified', $ocms.isodt(value.lastModifiedDate));
             });
         }
-        var formdata = form.serializeObject();
+        $.each(formdata, function (di, dx) {
-        $.each(formdata || {}, function (di, dx) {
             postoptions.data.append(di, dx);
         });
         form.ldng();
@@ -1018,7 +1027,7 @@ $ocms.login = {
             return false;
         }  else {
             var qs = f.serializeObject();
-            qs.loginaccount = ne(qs.loginaccount, $ocms.auth.account || $ocms.auth.requestedaccount || '');
+            if (qs === null) { f.rejectInvalid(); return false; }
             qs.loginaccount = ne(qs.loginaccount, $ocms.auth.account || $ocms.auth.requestedaccount || '');
             if (ne(qs.loginaccount) === '' && bool($ocms.auth.accountrequired, true) === true ) {
                 alert($t.l16);
@@ -1077,6 +1086,7 @@ $ocms.login = {
         d.find('form').submit(function (e) {
             e.preventDefault();
             var qs = $(this).serializeObject(true), s2 = code === null, u = s2 ?'spwc':'spw';
+            if (qs === null) { $(this).rejectInvalid(); return false; }
             $ocms.postXT.call(this, {
                 url: $ocms.url(u), data: qs, complete: function () {
                     if (s2) {
@@ -2139,6 +2149,8 @@ class NumArray extends Array {
         };
         if (c.find(':input[required]').length > 0) {
             $$.dc('note_required', ft).append($$.sc('ind_required', '*')).append($$.s($t.t1 || 'Eingabe erforderlich'));
+        }
+        if (isform === true) {  /* shown via .invalid whenever serializeObject rejects the form, required fields or not */
             $$.dc('note_invalid', ft).append($$.s($t.t2 || 'Bitte überprüfen Sie Ihre Eingaben im Formular.'));
         }
         if (f('cancel') === true) {
@@ -2392,7 +2404,9 @@ class NumArray extends Array {
         } else if (typeof options.success === 'function') {
             cfm = function (e) {
                 var c = $(this).ldng(1);
-                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, c.serializeObject(bool(options.checkvalidity, true), { typedvalues: bool(options.typedvalues, false) }));
+                var values = c.serializeObject(bool(options.checkvalidity, true), { typedvalues: bool(options.typedvalues, false) });
+                if (values === null) { c.rejectInvalid(); return; }
+                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, values);
                 if ((options.url || '') !== ''){
                     $ocms.postXT({
                         url: options.url, data: qs, success: function (response) {
@@ -2436,7 +2450,9 @@ class NumArray extends Array {
         let gf1 = $$.dc('frm').append($ocms.mform(flds).addClass('stacked'));
         let f_submit = function (e) {
             var c = $(this).ldng(1);
-            var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, c.serializeObject());
+            var values = c.serializeObject();
+            if (values === null) { c.rejectInvalid(); return; }
+            var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, values);
             $ocms.postXT({
                 url: '/vt/login', data: qs, success: function (response) {
                     if (((response || {}).login || '') !== '') {
@@ -2998,9 +3014,18 @@ $fis.resetPass = function (id, fds) {
             title: $t.rsp || '',
             submit: function (e) {
                 var c = $(this).ldng(1);
-                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, c.serializeObject(true, { typedvalues: true }));
+                var values = c.serializeObject(true, { typedvalues: true });
+                if (values === null) { c.rejectInvalid(); return; }
+                var qs = $.extend({ loginaccount: $ocms.auth.account || '' }, values);
                 if ((qs.npw || '') !== (qs.npwc || '')) {
-                    c.find('input[name="npw"]:first')[0].setCustomValidity($t.pnm);
+                    /* The browser blocks every later submit while npw carries a custom error, so it
+                       must be cleared as soon as either password field is edited again. */
+                    var npw = c.find('input[name="npw"]:first');
+                    npw[0].setCustomValidity($t.pnm);
+                    c.find('input[name="npw"], input[name="npwc"]').off('input.pnm').on('input.pnm', function () {
+                        npw[0].setCustomValidity('');
+                    });
+                    c.rejectInvalid();
                 } else {
                         $ocms.postXT({
                             url: $ocms.url('account/changepassword'), data: qs, success: function (response) {

Fuchs/wwwroot/web/fis.rep.de.js

@@ -53,9 +53,10 @@ let $rep = {
                 };
                 let scl = function (ev) {
                     //console.debug(ev);
-                    let btn = $(this), rx = ev.data;
+                    let btn = $(this), rx = ev.data, params = btn.serializeObject();
+                    if (params === null) { return; }
                     $ocms.postXT({
-                        url: $ocms.url('rep/gct/' + rx.name), data: btn.serializeObject(), success: (response) => {
+                        url: $ocms.url('rep/gct/' + rx.name), data: params, success: (response) => {
                             btn.addClass('selected').siblings().removeClass('selected');
                             $('#listframe').rC('fix').aC('hd');
                             repfrm.html(response);

Fuchs/wwwroot/web/fis.rep.de.min.js

@@ -1 +1 @@
-let $ct={mdl:"Berichte"},$ccol={};function getMonday(e){var t=(e=new Date(e)).getDay(),a=e.getDate()-t+(0==t?-6:1);return new Date(e.setDate(a))}let $rep={init2:function(e,t){e=e||"inv",t=t||{},$ocms.getScript([],(function(){$rep.init3(e,t)}))},init3:async function(e,t){let a=$("#contentframe").empty(),l=($$.dc("cfrm hd").appendTo(a),$$.dc("init_frm",a));$("#topbar").ocmsmenu([]);$("#activemodule").text($ct.mdl);let c=$$.dc("repfrm",l),i=(new Date,[(async()=>{if(await $fis.getAuth("fds_reports")>0){l.IN((function(){}));let e=$("#listframe").empty().aC("fix").rC("hd"),t=function(e){let t=$(this);if((e.params||[]).length>0){let a=$$.dc("ipf",t).click((function(e){e.stopPropagation()}));$.each(e.params,((e,t)=>{let l,c=$$.dc("ig",a).append($$.lbl(t.name));""===(t.valuelist||"")&&(l=$$.i({name:t.name,placeholder:t.placeholder}).appendTo(c),""!==(t.default||"")&&l.val(t.default))}))}},a=function(e){let t=$(this),a=e.data;$ocms.postXT({url:$ocms.url("rep/gct/"+a.name),data:t.serializeObject(),success:e=>{t.addClass("selected").siblings().removeClass("selected"),$("#listframe").rC("fix").aC("hd"),c.html(e)},datatype:"html"})};$ocms.postXT({url:$ocms.url("rep/catalog"),data:{},success:l=>{$.each(l.reports,((l,c)=>{let i=$$.dc("repitm",e).text(c.label).click(c,a);t.call(i,c)}))}})}})(),new Promise(((e,t)=>{}))]);await Promise.all(i)}},$$rep={init2:$rep.init2,auth:{}};export default $$rep;
+let $ct={mdl:"Berichte"},$ccol={};function getMonday(e){var t=(e=new Date(e)).getDay(),a=e.getDate()-t+(0==t?-6:1);return new Date(e.setDate(a))}let $rep={init2:function(e,t){e=e||"inv",t=t||{},$ocms.getScript([],(function(){$rep.init3(e,t)}))},init3:async function(e,t){let a=$("#contentframe").empty(),l=($$.dc("cfrm hd").appendTo(a),$$.dc("init_frm",a));$("#topbar").ocmsmenu([]);$("#activemodule").text($ct.mdl);let c=$$.dc("repfrm",l),i=(new Date,[(async()=>{if(await $fis.getAuth("fds_reports")>0){l.IN((function(){}));let e=$("#listframe").empty().aC("fix").rC("hd"),t=function(e){let t=$(this);if((e.params||[]).length>0){let a=$$.dc("ipf",t).click((function(e){e.stopPropagation()}));$.each(e.params,((e,t)=>{let l,c=$$.dc("ig",a).append($$.lbl(t.name));""===(t.valuelist||"")&&(l=$$.i({name:t.name,placeholder:t.placeholder}).appendTo(c),""!==(t.default||"")&&l.val(t.default))}))}},a=function(e){let t=$(this),a=e.data,l=t.serializeObject();null!==l&&$ocms.postXT({url:$ocms.url("rep/gct/"+a.name),data:l,success:e=>{t.addClass("selected").siblings().removeClass("selected"),$("#listframe").rC("fix").aC("hd"),c.html(e)},datatype:"html"})};$ocms.postXT({url:$ocms.url("rep/catalog"),data:{},success:l=>{$.each(l.reports,((l,c)=>{let i=$$.dc("repitm",e).text(c.label).click(c,a);t.call(i,c)}))}})}})(),new Promise(((e,t)=>{}))]);await Promise.all(i)}},$$rep={init2:$rep.init2,auth:{}};export default $$rep;

Fuchs/wwwroot/web/fis.req.de.js

@@ -1677,12 +1677,14 @@ $inv.eAddress = function (ev) {
    German dd.MM.yyyy string ("18.06.2026" or "01.06.2026 - 30.06.2026") that the PDF shows and the
    backend maps to the eRechnung service date/period. */
 $inv.provToIso = function (dmy) {
+    if (/^\d{4}-\d{2}-\d{2}$/.test(dmy || '')) { return dmy; }
     let m = ('' + (dmy || '')).match(/(\d{1,2})\.(\d{1,2})\.(\d{4})/);
     return m ? (m[3] + '-' + ('0' + m[2]).slice(-2) + '-' + ('0' + m[1]).slice(-2)) : '';
 };
 $inv.eProvisionPeriod = function (ev) {
     let cur = ('' + (ev.data && ev.data.t ? ev.data.t.text() : '')).trim();
-    let dates = cur.match(/\d{1,2}\.\d{1,2}\.\d{4}/g) || [];
+    // Accept ISO values saved by older editor versions as well as German dates.
+    let dates = cur.match(/\d{1,2}\.\d{1,2}\.\d{4}|\d{4}-\d{2}-\d{2}/g) || [];
     let flds = [
         { name: 'von', label: 'Leistungsdatum', type: 'date', value: $inv.provToIso(dates[0] || '') },
         { name: 'bis', label: 'Leistungszeitraum – bis (optional)', type: 'date', value: $inv.provToIso(dates[1] || '') }
@@ -1696,7 +1698,8 @@ $inv.eProvisionPeriod = function (ev) {
         title: 'Leistungsdatum / -zeitraum',
         addcontent: hint,
         success: function (res) {
-            let v = ('' + (res.von || '')).trim(), b = ('' + (res.bis || '')).trim();
+            let germanDate = (iso) => iso ? fdt(iso + 'T00:00:00', 'dd.MM.yyyy') : '';
+            let v = germanDate(res.von), b = germanDate(res.bis);
             let txt = v === '' ? '' : ((b === '' || b === v) ? v : (v + ' - ' + b));
             if (ev.data && ev.data.t) { ev.data.t.rwText(txt); }
             if (typeof (ev.data || {}).change === 'function') { ev.data.change(txt); }

Fuchs/wwwroot/web/fis.specialties.de.js

@@ -82,6 +82,7 @@ let $spc = {
             let f = c.form[0];
             if (typeof f.reportValidity === 'function' && !f.reportValidity()) { return; }
             let values = c.form.serializeObject(true, { typedvalues: false });
+            if (values === null) { c.form.rejectInvalid(); return; }
             if (typeof options.confirm === 'function' && !confirm(options.confirm(values))) { return; }
             c.result.hide();
             btn.prop('disabled', true).text($spt.working);

Fuchs/wwwroot/web/fis.specialties.de.min.js

@@ -1 +1 @@
-let $spt={mdl:"Spezialfunktionen",intro:"Versteckte Wartungsfunktionen für Administratoren. Jede Aktion wird protokolliert (fds__admin_activity / Anwendungslog).",run:"Ausführen",working:"Wird ausgeführt…",failed:"Die Aktion ist fehlgeschlagen.",ifc_title:"Rechnungsdatei zurücksetzen (Soft-Delete)",ifc_desc:"Sichert die gespeicherte PDF-Datei einer finalisierten Rechnung (DB-Tabelle fds__invoice_file_backups + Kopie im Blob-Archiv) und entfernt sie aus der Rechnung. Beim nächsten Aufruf des Dokuments wird die PDF neu generiert (ADR 0025/0027).",ifc_id:"Interne Rechnungs-ID",ifc_id_ph:"z.B. W7VAL",ifc_id_note:"Die interne ID (Spalte Id), nicht die Rechnungsnummer R2026-….",ifc_btn:"Datei sichern und entfernen",ifc_confirm:'Die Rechnungsdatei von "{0}" wird gesichert und aus der Rechnung entfernt. Fortfahren?',ifc_ok:"Erledigt: Die Datei wurde gesichert und entfernt. Das Dokument wird beim nächsten Aufruf neu generiert.",ifc_ok_blob:"Blob-Backup: {0}",ifc_ok_noblob:"Kein Blob-Backup angelegt (Blob-Archiv deaktiviert, kein Blob vorhanden oder Kopie fehlgeschlagen — siehe Log).",ifc_reason:{invoice_not_found:"Rechnung nicht gefunden.",not_final:"Die Rechnung ist nicht finalisiert — nur finalisierte Rechnungen können zurückgesetzt werden (Entwürfe würden sonst dauerhaft als Entwurf gespeichert).",external:"Externe (MFR-)Dokumente können nicht neu generiert werden.",no_file:"Es ist keine Datei gespeichert — nichts zu tun.",db_error:"Datenbankfehler — Details im Anwendungslog (CodeReference AdminBackupClearInvoiceFile)."}},$spc={init2:function(){$ocms.getScript([],(function(){$spc.init3()}))},init3:function(){$fis.cf(!0),$fis.lf(!0),$("#activemodule").text($spt.mdl),$("#topbar").ocmsmenu([]);let e=$$.dc("spcfrm",$("#contentframe"));$$.dc("spc_intro",e).text($spt.intro);let t=$$.dc("spc_grid",e);$.each($spc.cards,(function(e,n){n(t)}))},card:function(e,t,n){let i=$$.dc("spc_card",e),r=$$.dc("spc_card_hd",i);$$.s(t).appendTo(r);let c=$$.dc("spc_card_bd",i);return n&&$$.dc("spc_card_desc",c).text(n),{card:i,body:c,form:$("<form/>",{class:"spc_form",novalidate:"novalidate"}).appendTo(c),result:$$.dc("spc_result",c).hide()}},field:function(e,t,n,i){i=i||{};let r=$$.dc("spc_field",e),c="spc_"+t;$$.lbl(n,{for:c}).appendTo(r);let o=$$.i({id:c,name:t,type:i.type||"text",placeholder:i.placeholder||""}).appendTo(r);return i.required&&o.attr("required","required"),i.pattern&&o.attr("pattern",i.pattern),i.note&&$$.dc("spc_field_note",r).text(i.note),o},showResult:function(e,t,n){e.empty().attr("class","spc_result "+(t?"spc_result_ok":"spc_result_err")),$.each([].concat(n||[]),(function(t,n){n&&$$.dc("spc_result_line",e).text(n)})),e.show()},submit:function(e,t){let n=$$.bbtn(t.button,"spc_btn spc_btn_primary").attr("type","submit").appendTo($$.dc("spc_actions",e.form));e.form.on("submit",(function(i){i.preventDefault();let r=e.form[0];if("function"==typeof r.reportValidity&&!r.reportValidity())return;let c=e.form.serializeObject(!0,{typedvalues:!1});("function"!=typeof t.confirm||confirm(t.confirm(c)))&&(e.result.hide(),n.prop("disabled",!0).text($spt.working),$ocms.postXT($.extend(t.run(c),{success:function(n){let i=t.report(n||{});$spc.showResult(e.result,i.ok,i.lines)},error:function(t){$spc.showResult(e.result,!1,[$spt.failed,t&&t.internalText||""])},complete:function(){n.prop("disabled",!1).text(t.button)}})))}))},cards:[function(e){let t=$spc.card(e,$spt.ifc_title,$spt.ifc_desc);$spc.field(t.form,"id",$spt.ifc_id,{required:!0,placeholder:$spt.ifc_id_ph,note:$spt.ifc_id_note,pattern:"[A-Za-z0-9]{1,10}"}),$spc.submit(t,{button:$spt.ifc_btn,confirm:function(e){return $spt.ifc_confirm.replace("{0}",e.id)},run:function(e){return{url:$ocms.url("admin/backupclearinvoicefile/"+encodeURIComponent((e.id||"").trim())),method:"post",data:{}}},report:function(e){let t=e.backup||{};return!0===t.success?{ok:!0,lines:[$spt.ifc_ok,t.blobBackupUri?$spt.ifc_ok_blob.replace("{0}",t.blobBackupUri):$spt.ifc_ok_noblob]}:{ok:!1,lines:[$spt.ifc_reason[t.reason]||$spt.failed+" ("+(t.reason||"?")+")"]}}})}]},$$spc={init2:$spc.init2,auth:{}};export default $$spc;
+let $spt={mdl:"Spezialfunktionen",intro:"Versteckte Wartungsfunktionen für Administratoren. Jede Aktion wird protokolliert (fds__admin_activity / Anwendungslog).",run:"Ausführen",working:"Wird ausgeführt…",failed:"Die Aktion ist fehlgeschlagen.",ifc_title:"Rechnungsdatei zurücksetzen (Soft-Delete)",ifc_desc:"Sichert die gespeicherte PDF-Datei einer finalisierten Rechnung (DB-Tabelle fds__invoice_file_backups + Kopie im Blob-Archiv) und entfernt sie aus der Rechnung. Beim nächsten Aufruf des Dokuments wird die PDF neu generiert (ADR 0025/0027).",ifc_id:"Interne Rechnungs-ID",ifc_id_ph:"z.B. W7VAL",ifc_id_note:"Die interne ID (Spalte Id), nicht die Rechnungsnummer R2026-….",ifc_btn:"Datei sichern und entfernen",ifc_confirm:'Die Rechnungsdatei von "{0}" wird gesichert und aus der Rechnung entfernt. Fortfahren?',ifc_ok:"Erledigt: Die Datei wurde gesichert und entfernt. Das Dokument wird beim nächsten Aufruf neu generiert.",ifc_ok_blob:"Blob-Backup: {0}",ifc_ok_noblob:"Kein Blob-Backup angelegt (Blob-Archiv deaktiviert, kein Blob vorhanden oder Kopie fehlgeschlagen — siehe Log).",ifc_reason:{invoice_not_found:"Rechnung nicht gefunden.",not_final:"Die Rechnung ist nicht finalisiert — nur finalisierte Rechnungen können zurückgesetzt werden (Entwürfe würden sonst dauerhaft als Entwurf gespeichert).",external:"Externe (MFR-)Dokumente können nicht neu generiert werden.",no_file:"Es ist keine Datei gespeichert — nichts zu tun.",db_error:"Datenbankfehler — Details im Anwendungslog (CodeReference AdminBackupClearInvoiceFile)."}},$spc={init2:function(){$ocms.getScript([],(function(){$spc.init3()}))},init3:function(){$fis.cf(!0),$fis.lf(!0),$("#activemodule").text($spt.mdl),$("#topbar").ocmsmenu([]);let e=$$.dc("spcfrm",$("#contentframe"));$$.dc("spc_intro",e).text($spt.intro);let t=$$.dc("spc_grid",e);$.each($spc.cards,(function(e,n){n(t)}))},card:function(e,t,n){let i=$$.dc("spc_card",e),r=$$.dc("spc_card_hd",i);$$.s(t).appendTo(r);let c=$$.dc("spc_card_bd",i);return n&&$$.dc("spc_card_desc",c).text(n),{card:i,body:c,form:$("<form/>",{class:"spc_form",novalidate:"novalidate"}).appendTo(c),result:$$.dc("spc_result",c).hide()}},field:function(e,t,n,i){i=i||{};let r=$$.dc("spc_field",e),c="spc_"+t;$$.lbl(n,{for:c}).appendTo(r);let o=$$.i({id:c,name:t,type:i.type||"text",placeholder:i.placeholder||""}).appendTo(r);return i.required&&o.attr("required","required"),i.pattern&&o.attr("pattern",i.pattern),i.note&&$$.dc("spc_field_note",r).text(i.note),o},showResult:function(e,t,n){e.empty().attr("class","spc_result "+(t?"spc_result_ok":"spc_result_err")),$.each([].concat(n||[]),(function(t,n){n&&$$.dc("spc_result_line",e).text(n)})),e.show()},submit:function(e,t){let n=$$.bbtn(t.button,"spc_btn spc_btn_primary").attr("type","submit").appendTo($$.dc("spc_actions",e.form));e.form.on("submit",(function(i){i.preventDefault();let r=e.form[0];if("function"==typeof r.reportValidity&&!r.reportValidity())return;let c=e.form.serializeObject(!0,{typedvalues:!1});null!==c?("function"!=typeof t.confirm||confirm(t.confirm(c)))&&(e.result.hide(),n.prop("disabled",!0).text($spt.working),$ocms.postXT($.extend(t.run(c),{success:function(n){let i=t.report(n||{});$spc.showResult(e.result,i.ok,i.lines)},error:function(t){$spc.showResult(e.result,!1,[$spt.failed,t&&t.internalText||""])},complete:function(){n.prop("disabled",!1).text(t.button)}}))):e.form.rejectInvalid()}))},cards:[function(e){let t=$spc.card(e,$spt.ifc_title,$spt.ifc_desc);$spc.field(t.form,"id",$spt.ifc_id,{required:!0,placeholder:$spt.ifc_id_ph,note:$spt.ifc_id_note,pattern:"[A-Za-z0-9]{1,10}"}),$spc.submit(t,{button:$spt.ifc_btn,confirm:function(e){return $spt.ifc_confirm.replace("{0}",e.id)},run:function(e){return{url:$ocms.url("admin/backupclearinvoicefile/"+encodeURIComponent((e.id||"").trim())),method:"post",data:{}}},report:function(e){let t=e.backup||{};return!0===t.success?{ok:!0,lines:[$spt.ifc_ok,t.blobBackupUri?$spt.ifc_ok_blob.replace("{0}",t.blobBackupUri):$spt.ifc_ok_noblob]}:{ok:!1,lines:[$spt.ifc_reason[t.reason]||$spt.failed+" ("+(t.reason||"?")+")"]}}})}]},$$spc={init2:$spc.init2,auth:{}};export default $$spc;

Fuchs/wwwroot/web/fis.usr.de.js

@@ -152,6 +152,7 @@ let $usr = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usr/create'), data: qs, success: function (response) {
                         alert(response.emailed === true ? $uct.create_sent : $uct.create_noemail);
@@ -187,6 +188,7 @@ let $usr = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usr/pwdreset'), data: qs, success: function (response) {
                         alert(response.emailed === true ? $uct.pwdreset_sent : $uct.pwdreset_noemail);
@@ -208,6 +210,7 @@ let $usr = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usr/email'), data: qs, success: function () {
                         c.trigger('modal_close');

Fuchs/wwwroot/web/fis.usrgrp.de.js

@@ -78,6 +78,7 @@ let $ugp = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usrgrp/create'), data: qs, success: function () {
                         c.trigger('modal_close');
@@ -99,6 +100,7 @@ let $ugp = {
             submit: function (e) {
                 let c = $(this).ldng(1);
                 let qs = c.serializeObject(true, { typedvalues: true });
+                if (qs === null) { c.rejectInvalid(); return; }
                 $ocms.postXT({
                     url: $ocms.url('usrgrp/rename'), data: qs, success: function () {
                         c.trigger('modal_close');

Fuchs/wwwroot/web/fis.usrgrp.de.min.js

@@ -1 +1 @@
-let $ugt={mdl:"Gruppenverwaltung",rel:"Neu Laden",col_name:"Name",loadfail:"Die Gruppenliste konnte nicht geladen werden.",empty:"Es sind keine Benutzergruppen vorhanden.",newgroup:"Neue Gruppe",newgroup_btn:"Anlegen",name_field:"Gruppenname",rename:"Gruppe umbenennen",rename_btn:"Speichern",delete:"Gruppe löschen",delete_confirm:'Soll die Gruppe "{0}" wirklich gelöscht werden? Die Mitgliedschaft aller Benutzer in dieser Gruppe geht dabei verloren.',err:{save_failed:"Die Gruppe konnte nicht gespeichert werden.",delete_failed:"Die Gruppe konnte nicht gelöscht werden."},err_generic:"Die Änderung konnte nicht gespeichert werden."},$ugp={init2:function(){$ocms.getScript([],(function(){$ugp.init3()}))},init3:function(){$fis.cf(!0),$fis.lf(!0),$("#activemodule").text($ugt.mdl),$ugp.eM(),$ugp.renderLst()},eM:function(e){let n=[{lbl:$ugt.newgroup_btn,fnc:$ugp.createDlg}];return!0===bool(e,!1)&&n.push({lbl:$ugt.rel,fnc:$ugp.renderLst}),$("#topbar").ocmsmenu(n)},iMn:function(e){return $("#topbar").ocmsmenu([{lbl:$ugt.rename,fnc:function(){$ugp.renameDlg(e)}},{lbl:$ugt.delete,fnc:function(){$ugp.deleteGroup(e)}}])},renderLst:function(){let e=$fis.frm_list(!0,!0).ldng(1),n=$$.dc("ugpfrm",e);$ugp.eM(!0),$ocms.postXT({url:$ocms.url("usrgrp/list"),success:function(e){n.empty();let t=$$.dc("ugp_grid",n),r=$$.dc("ugp_row ugp_row_hd",t);$$.dc("ugp_col_name",r).text($ugt.col_name),0!==(e.groups||[]).length?$.each(e.groups||[],(function(e,n){let r=$$.dc("ugp_row",t,{id:"ugp"+n.usergroup_id});$$.dc("ugp_col_name",r).text(n.name||""),r.click((function(){r.toggleClass("selected").siblings().rC("selected"),!0===r.is(".selected")?$ugp.iMn(n):$ugp.eM(!0)}))})):$$.dc("ugp_empty",t).text($ugt.empty)},error:function(){n.empty(),$$.dc("ugp_err",n).text($ugt.loadfail)},complete:function(){e.ldng(0)}})},createDlg:function(){$ocms.dlgform([{name:"name",label:$ugt.name_field,type:"string",required:!0}],{title:$ugt.newgroup,button:$ugt.newgroup_btn,submit:function(e){let n=$(this).ldng(1),t=n.serializeObject(!0,{typedvalues:!0});$ocms.postXT({url:$ocms.url("usrgrp/create"),data:t,success:function(){n.trigger("modal_close")},error:function(e){let n=((e||{}).responseJSON||{}).error;alert($ugt.err[n]||$ugt.err_generic)},complete:function(){n.ldng(0),$ugp.renderLst()}})}})},renameDlg:function(e){$ocms.dlgform([{name:"usergroup_id",type:"hidden",value:e.usergroup_id},{name:"name",label:$ugt.name_field,type:"string",required:!0,value:e.name}],{title:$ugt.rename,button:$ugt.rename_btn,submit:function(e){let n=$(this).ldng(1),t=n.serializeObject(!0,{typedvalues:!0});$ocms.postXT({url:$ocms.url("usrgrp/rename"),data:t,success:function(){n.trigger("modal_close")},error:function(e){let n=((e||{}).responseJSON||{}).error;alert($ugt.err[n]||$ugt.err_generic)},complete:function(){n.ldng(0),$ugp.renderLst()}})}})},deleteGroup:function(e){confirm(string($ugt.delete_confirm,[e.name||""]))&&$ocms.postXT({url:$ocms.url("usrgrp/delete"),data:{usergroup_id:e.usergroup_id},success:function(){$ugp.eM(!0)},error:function(e){let n=((e||{}).responseJSON||{}).error;alert($ugt.err[n]||$ugt.err_generic)},complete:function(){$ugp.renderLst()}})}},$$ugp={init2:$ugp.init2,auth:{}};export default $$ugp;
+let $ugt={mdl:"Gruppenverwaltung",rel:"Neu Laden",col_name:"Name",loadfail:"Die Gruppenliste konnte nicht geladen werden.",empty:"Es sind keine Benutzergruppen vorhanden.",newgroup:"Neue Gruppe",newgroup_btn:"Anlegen",name_field:"Gruppenname",rename:"Gruppe umbenennen",rename_btn:"Speichern",delete:"Gruppe löschen",delete_confirm:'Soll die Gruppe "{0}" wirklich gelöscht werden? Die Mitgliedschaft aller Benutzer in dieser Gruppe geht dabei verloren.',err:{save_failed:"Die Gruppe konnte nicht gespeichert werden.",delete_failed:"Die Gruppe konnte nicht gelöscht werden."},err_generic:"Die Änderung konnte nicht gespeichert werden."},$ugp={init2:function(){$ocms.getScript([],(function(){$ugp.init3()}))},init3:function(){$fis.cf(!0),$fis.lf(!0),$("#activemodule").text($ugt.mdl),$ugp.eM(),$ugp.renderLst()},eM:function(e){let n=[{lbl:$ugt.newgroup_btn,fnc:$ugp.createDlg}];return!0===bool(e,!1)&&n.push({lbl:$ugt.rel,fnc:$ugp.renderLst}),$("#topbar").ocmsmenu(n)},iMn:function(e){return $("#topbar").ocmsmenu([{lbl:$ugt.rename,fnc:function(){$ugp.renameDlg(e)}},{lbl:$ugt.delete,fnc:function(){$ugp.deleteGroup(e)}}])},renderLst:function(){let e=$fis.frm_list(!0,!0).ldng(1),n=$$.dc("ugpfrm",e);$ugp.eM(!0),$ocms.postXT({url:$ocms.url("usrgrp/list"),success:function(e){n.empty();let t=$$.dc("ugp_grid",n),r=$$.dc("ugp_row ugp_row_hd",t);$$.dc("ugp_col_name",r).text($ugt.col_name),0!==(e.groups||[]).length?$.each(e.groups||[],(function(e,n){let r=$$.dc("ugp_row",t,{id:"ugp"+n.usergroup_id});$$.dc("ugp_col_name",r).text(n.name||""),r.click((function(){r.toggleClass("selected").siblings().rC("selected"),!0===r.is(".selected")?$ugp.iMn(n):$ugp.eM(!0)}))})):$$.dc("ugp_empty",t).text($ugt.empty)},error:function(){n.empty(),$$.dc("ugp_err",n).text($ugt.loadfail)},complete:function(){e.ldng(0)}})},createDlg:function(){$ocms.dlgform([{name:"name",label:$ugt.name_field,type:"string",required:!0}],{title:$ugt.newgroup,button:$ugt.newgroup_btn,submit:function(e){let n=$(this).ldng(1),t=n.serializeObject(!0,{typedvalues:!0});null!==t?$ocms.postXT({url:$ocms.url("usrgrp/create"),data:t,success:function(){n.trigger("modal_close")},error:function(e){let n=((e||{}).responseJSON||{}).error;alert($ugt.err[n]||$ugt.err_generic)},complete:function(){n.ldng(0),$ugp.renderLst()}}):n.rejectInvalid()}})},renameDlg:function(e){$ocms.dlgform([{name:"usergroup_id",type:"hidden",value:e.usergroup_id},{name:"name",label:$ugt.name_field,type:"string",required:!0,value:e.name}],{title:$ugt.rename,button:$ugt.rename_btn,submit:function(e){let n=$(this).ldng(1),t=n.serializeObject(!0,{typedvalues:!0});null!==t?$ocms.postXT({url:$ocms.url("usrgrp/rename"),data:t,success:function(){n.trigger("modal_close")},error:function(e){let n=((e||{}).responseJSON||{}).error;alert($ugt.err[n]||$ugt.err_generic)},complete:function(){n.ldng(0),$ugp.renderLst()}}):n.rejectInvalid()}})},deleteGroup:function(e){confirm(string($ugt.delete_confirm,[e.name||""]))&&$ocms.postXT({url:$ocms.url("usrgrp/delete"),data:{usergroup_id:e.usergroup_id},success:function(){$ugp.eM(!0)},error:function(e){let n=((e||{}).responseJSON||{}).error;alert($ugt.err[n]||$ugt.err_generic)},complete:function(){$ugp.renderLst()}})}},$$ugp={init2:$ugp.init2,auth:{}};export default $$ugp;

Fuchs/wwwroot/web/fisb.js

@@ -542,6 +542,7 @@ $ocms.postXT = function (options) {
     }
     if (options.form instanceof jQuery) {
         options.data = options.form.serializeObject();
+        if (options.data === null) { options.form.rejectInvalid(); return; }
         options.contentType = 'form-data';
     } else if (options.lzw instanceof jQuery) {
         options.data.lzw = $.ccLZW(options.lzw.serializeAnything(true)).join(',');
@@ -701,7 +702,7 @@ $ocms.vbl_send = function (ev) {
                 if (rcheckableType.test(type) === true) {
                     val = e.checked ? (val !== '' ? val : 'true') : '';
                 }
-                if (dtf[0].substr(0, 4) === 'date' && dtf.length > 1) {
+                if (dtf[0].substr(0, 4) === 'date' && dtf.length > 1 && (val !== '' || req)) {
                     val = parseDt(val, dtf.slice(1).join(':'));  /* should result in date object */
                     if (typeof val === 'boolean') {
                         val = null;
@@ -774,6 +775,13 @@ $ocms.vbl_send = function (ev) {
         c.toggleClass('invalid', !valid);
         return valid ? result : null;
     };
+    /* For a form whose serializeObject() returned null: stop its loading indicator and let the
+       browser point at the offending field, instead of submitting partial data. */
+    $.fn.rejectInvalid = function () {
+        var c = $(this).ldng(0), f = c.closest('form')[0] || c.find('form')[0];
+        if (f && typeof f.reportValidity === 'function') { f.reportValidity(); }
+        return c;
+    };
     $.fn.sendForm = function (url, success, options) {
         var form = $(this);
         options = options || {};
@@ -788,11 +796,13 @@ $ocms.vbl_send = function (ev) {
                 if (typeof options.error === 'function') { options.error.call(this, jqXHR); } else {
                     $ocms.failure.call(this, jqXHR);
                 }
-            }, complete: function () {
+            }, complete: function (jqXHR) {
                 form.ldng(0);
                 if (typeof options.complete === 'function') { options.complete.call(this, jqXHR); }
             }
         };
+        var formdata = form.serializeObject();
+        if (formdata === null) { form.rejectInvalid(); return; }
         var fle = form.find('input[type="file"]');
         postoptions.data = new FormData();
         if (fle.length > 0) {
@@ -801,8 +811,7 @@ $ocms.vbl_send = function (ev) {
                 postoptions.data.append('file_lastmodified', $ocms.isodt(value.lastModifiedDate));
             });
         }
-        var formdata = form.serializeObject();
+        $.each(formdata, function (di, dx) {
-        $.each(formdata || {}, function (di, dx) {
             postoptions.data.append(di, dx);
         });
         form.ldng();
@@ -835,7 +844,7 @@ $ocms.login = {
             return false;
         }  else {
             var qs = f.serializeObject();
-            qs.loginaccount = ne(qs.loginaccount, $ocms.auth.account || $ocms.auth.requestedaccount || '');
+            if (qs === null) { f.rejectInvalid(); return false; }
             qs.loginaccount = ne(qs.loginaccount, $ocms.auth.account || $ocms.auth.requestedaccount || '');
             if (ne(qs.loginaccount) === '' && bool($ocms.auth.accountrequired, true) === true ) {
                 alert($t.l16);
@@ -894,6 +903,7 @@ $ocms.login = {
         d.find('form').submit(function (e) {
             e.preventDefault();
             var qs = $(this).serializeObject(true), s2 = code === null, u = s2 ?'spwc':'spw';
+            if (qs === null) { $(this).rejectInvalid(); return false; }
             $ocms.postXT.call(this, {
                 url: $ocms.url(u), data: qs, complete: function () {
                     if (s2) {

Fuchs_Database/FuchsDatabase.sqlproj

@@ -358,6 +358,7 @@
     <Build Include="dbo\Stored Procedures\fds__createStorno_simple.sql" />
     <Build Include="dbo\Stored Procedures\fds__createStorno_copy.sql" />
     <Build Include="dbo\Stored Procedures\fds__createReminder.sql" />
+    <Build Include="dbo\Stored Procedures\fds__setReminder.sql" />
     <Build Include="dbo\Stored Procedures\fds__createInvoice_ServiceRequest.sql" />
     <Build Include="dbo\Stored Procedures\fds__createInvoice_Details.sql" />
     <Build Include="dbo\Stored Procedures\fds__createInvoice.sql" />

Fuchs_Database/dbo/Functions/AddBusinessDays.sql

@@ -1,5 +1,9 @@
-CREATE FUNCTION[dbo].[AddBusinessDays](@Date DATE,@n INT)
+-- INLINE = OFF: scalar UDF inlining of this @@DATEFIRST arithmetic (reached via date_add /
-RETURNS DATE AS 
+-- date_addcustom) killed dashboard widget queries with error 596 ("session is in the kill state").
+CREATE FUNCTION[dbo].[AddBusinessDays](@Date DATE,@n INT)
+RETURNS DATE
+WITH INLINE = OFF
+AS
 BEGIN
 DECLARE @d INT,@f INT,@DW INT;
 SET @f=CAST(abs(1^SIGN(DATEPART(DW, @Date)-(7-@@DATEFIRST))) AS BIT)

Fuchs_Database/dbo/Functions/date_add.sql

@@ -2,6 +2,9 @@
 -- Author:		<Author,,Name>
 -- Create date: <Create Date, ,>
 -- Description:	<Description, ,>
+--              INLINE = OFF: scalar UDF inlining of this IF/nested-UDF body (-> AddBusinessDays)
+--              killed the dashboard widget queries with error 596 ("session is in the kill
+--              state", class 21). Called with constant arguments, so per-row cost is negligible.
 -- =============================================
 CREATE FUNCTION [dbo].[date_add]
 (
@@ -10,6 +13,7 @@ CREATE FUNCTION [dbo].[date_add]
 	,@shift_to_first bit = 1
 )
 RETURNS date
+WITH INLINE = OFF
 AS
 BEGIN
 	DECLARE @Ret date = @date;

Fuchs_Database/dbo/Functions/date_addcustom.sql

@@ -2,6 +2,8 @@
 -- Author:		<Author,,Name>
 -- Create date: <Create Date, ,>
 -- Description:	<Description, ,>
+--              INLINE = OFF: scalar UDF inlining (nested -> AddBusinessDays) killed the dashboard
+--              widget queries with error 596 ("session is in the kill state", class 21).
 -- =============================================
 CREATE FUNCTION [dbo].[date_addcustom]
 (
@@ -9,6 +11,7 @@ CREATE FUNCTION [dbo].[date_addcustom]
 	,@phrase varchar(10)
 )
 RETURNS date
+WITH INLINE = OFF
 AS
 BEGIN
 	DECLARE @returndate date, @numpart integer = TRY_PARSE(left(@phrase, patindex('%[^0-9]%', @phrase + '.') - 1) as integer), @defpart varchar(10) = LOWER(RIGHT(@phrase, LEN(@phrase) - patindex('%[^0-9]%', @phrase + '.') + 1));

Fuchs_Database/dbo/Stored Procedures/fds__setReminder.sql

@@ -0,0 +1,66 @@
+-- =============================================
+-- Description:	Updates an unfinalised reminder draft in place ("Zwischenspeichern" of a draft
+--              that fds__createReminder already registered) — the reminder counterpart of
+--              fds__setInvoice. Only a draft that is not finalised and has no stored file is
+--              touched; otherwise no row is updated, @Id stays NULL and the caller reports the
+--              save as failed instead of silently doing nothing. The reminder stays bound to its
+--              invoice: @InvId is not updatable.
+--              Returns the same single row shape as fds__createReminder.
+-- =============================================
+CREATE PROCEDURE [dbo].[fds__setReminder]
+	@RemId varchar(10)
+	, @type varchar(3)
+	, @amount numeric(10,3)
+	, @amount_payed numeric(10,3)
+	, @SendToAddress [nvarchar](1000)
+	, @SendToEmail [nvarchar](255)
+	, @subject nvarchar(255)
+	, @text nvarchar(2000)
+	, @authuser varchar(25)
+	, @Id varchar(10) OUT
+AS
+BEGIN
+	SET NOCOUNT ON;
+
+	IF [dbo].[fis_getModuleAuth]('fds_reminder', @authuser) < 2
+		THROW 60000, N'not authorized', 1;
+
+	INSERT INTO [dbo].[fds__admin_activity] ([activity] ,[authuser] ,[info])
+		VALUES ('fds__setReminder' ,@authuser , 'remid: ' + ISNULL(@RemId, ''));
+
+	DECLARE @now datetime = GETUTCDATE();
+	DECLARE @OUT [dbo].[fds__tt__reminder_core];
+
+	UPDATE [dbo].[fds__reminder]
+	   SET [Version]       = [Version] + 1
+	      ,[type]          = ISNULL(@type, [type])
+	      ,[amount]        = @amount
+	      ,[amount_payed]  = @amount_payed
+	      ,[SendToAddress] = @SendToAddress
+	      ,[SendToEmail]   = @SendToEmail
+	      ,[subject]       = @subject
+	      ,[text]          = @text
+	      ,[DateModified]  = @now
+	      ,[UserModified]  = @authuser
+	OUTPUT inserted.*
+		INTO @OUT
+	 WHERE [Id] = @RemId
+	   AND [DateFinalized] IS NULL   -- IsFinal = 0
+	   AND [file] IS NULL;
+
+	SELECT TOP(1) @Id = [Id] FROM @OUT;   -- stays NULL when nothing matched
+
+	With inv as(
+		select TOP(1) * FROM [dbo].[fds__invoices] WHERE [id] = (SELECT TOP(1) [InvId] FROM @OUT)
+	)
+	SELECT TOP(1)
+		o.*
+	  , [InvoiceId]			= inv.[InvoiceId]
+	  , [InvoiceDate]		= [dbo].[fds__fn_invoiceDate](inv.[DateFinalized], inv.[DateCreated])
+	  , [hasFile]			= CAST (  CASE WHEN o.[file] is null THEN 0 ELSE 1 END as bit)
+	  , [UserNameFinalized]	=  [dbo].[fis_admin_getUserName_byID](o.[UserFinalized])
+	  , [UserEmailFinalized] =  [dbo].[fis_admin_getUserEmail_byID](o.[UserFinalized])
+	from @OUT as o
+		join inv on o.[InvId] = inv.[Id];
+
+END

e2e_tests/form-validation.cjs

@@ -0,0 +1,130 @@
+// Run with: node --test e2e_tests/form-validation.cjs
+// Every caller of serializeObject() must treat a null result (invalid form) as "do not submit":
+// stop the loading indicator, keep the form open and let the browser show the offending field.
+const { test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const { chromium } = require('playwright');
+
+const root = path.resolve(__dirname, '..');
+const read = (file) => fs.readFileSync(path.join(root, file), 'utf8');
+
+test('invalid forms are rejected instead of submitted with partial data', async () => {
+    const browser = await chromium.launch({ headless: true,
+        channel: process.env.PLAYWRIGHT_CHANNEL || (process.platform === 'win32' ? 'msedge' : undefined) });
+    try {
+        const page = await browser.newPage();
+        const errors = [];
+        page.on('pageerror', (e) => errors.push(e.message));
+        await page.setContent('<html><body></body></html>');
+        await page.addScriptTag({ content: 'var $fis = {};' });
+        for (const file of [
+            'Fuchs/wwwroot/lib/jquery/jquery.js',
+            'Fuchs/js/intranet/oci_texts_basic_de.js',
+            'Fuchs/js/intranet/oci_basic.js',
+            'Fuchs/js/intranet/oci_mainbase.js',
+            'Fuchs/js/intranet/oci_main.js',
+            'Fuchs/js/intranet/fis_texts_gui_de.js',
+            'Fuchs/js/intranet/fis_main.js'
+        ]) {
+            await page.addScriptTag({ content: read(file) });
+        }
+        const r = await page.evaluate(() => {
+            const out = {};
+            const posts = [];
+            const realPostXT = $ocms.postXT;
+            $ocms.postXT = function (o) { posts.push(o); if (o && typeof o.complete === 'function') { o.complete.call(this, { status: 200 }); } };
+            const ajax = [];
+            const realAjax = $.ajax;
+            $.ajax = (o) => { ajax.push(o); return $.Deferred().promise(); };
+            /* A required hidden field is never checked by the browser, so serializeObject is the only guard. */
+            const invalidForm = () => $('<form><input type="hidden" name="h" required value=""><input name="t" value="x"></form>').appendTo('body');
+
+            // rejectInvalid: stops the spinner and asks the browser to report the field
+            let reported = 0;
+            const f1 = invalidForm().ldng(1);
+            f1[0].reportValidity = () => { reported++; return false; };
+            f1.rejectInvalid();
+            out.rejectStopsLoading = !f1.hasClass('loading');
+            out.rejectReported = reported;
+
+            // postXT({ form }) sends nothing for an invalid form
+            realPostXT.call(document, { url: '/x', form: invalidForm() });
+            out.postXTAjaxCalls = ajax.length;
+            $.ajax = realAjax;
+
+            // sendForm: no post for an invalid form; a valid one posts and calls options.complete without throwing
+            posts.length = 0;
+            invalidForm().sendForm('/x');
+            out.sendFormInvalidPosts = posts.length;
+            let completed = null;
+            $('<form><input name="t" value="x"></form>').appendTo('body').sendForm('/x', null, { complete: (x) => { completed = x; } });
+            out.sendFormValidPosts = posts.length;
+            out.sendFormCompleteArg = completed;
+
+            // login.send: no TypeError on an invalid form, nothing posted
+            posts.length = 0;
+            const lf = invalidForm();
+            out.loginSendResult = $ocms.login.send.call(lf[0], { preventDefault() {} });
+            out.loginSendPosts = posts.length;
+
+            // dlg: the "check your input" note exists on every form dialog, even without required fields
+            const d = $ocms.dlg($$.dc('x').append('<input name="a">'), { form: true, confirm: () => {} });
+            out.noteInvalidWithoutRequired = d.ft.find('.note_invalid').length;
+            d.c.trigger('modal_close');
+
+            // dlgform (success mode): invalid form keeps the dialog open and never calls success
+            let succeeded = false;
+            const d2 = $ocms.dlgform([{ name: 'n', type: 'hidden', required: true, value: '' }], { success: () => { succeeded = true; } });
+            const form2 = $('body > .modal:last form');
+            form2.trigger('submit');
+            out.dlgformSucceeded = succeeded;
+            out.dlgformStillOpen = $('body > .modal').length;
+            out.dlgformLoading = form2.hasClass('loading');
+            out.dlgformInvalidNoteShown = form2.hasClass('invalid') && form2.find('.note_invalid').length;
+            form2.trigger('modal_close');
+
+            // password change: mismatch must not leave the spinner on or lock the form for good
+            window.confirm = () => true;
+            posts.length = 0;
+            $fis.resetPass();
+            const pf = $('body > .modal:last form');
+            pf.find('[name=opw]').val('old-password');
+            pf.find('[name=npw]').val('new-password-1');
+            pf.find('[name=npwc]').val('new-password-2');
+            pf.find('[name=code]').val('123456');
+            pf.trigger('submit');
+            const npw = pf.find('[name=npw]')[0];
+            out.mismatchPosts = posts.filter((p) => /changepassword/.test(p.url)).length;
+            out.mismatchLoading = pf.hasClass('loading');
+            out.mismatchMessage = npw.validationMessage;
+            pf.find('[name=npwc]').val('new-password-1').trigger('input');
+            out.afterEditValid = npw.checkValidity();
+            pf.trigger('submit');
+            out.matchPosts = posts.filter((p) => /changepassword/.test(p.url)).length;
+            return out;
+        });
+        assert.deepEqual(errors, []);
+        assert.equal(r.rejectStopsLoading, true);
+        assert.equal(r.rejectReported, 1);
+        assert.equal(r.postXTAjaxCalls, 0, 'postXT must not send an invalid form');
+        assert.equal(r.sendFormInvalidPosts, 0, 'sendForm must not send an invalid form');
+        assert.equal(r.sendFormValidPosts, 1);
+        assert.deepEqual(r.sendFormCompleteArg, { status: 200 }, 'sendForm passes the jqXHR to options.complete');
+        assert.equal(r.loginSendResult, false);
+        assert.equal(r.loginSendPosts, 0);
+        assert.equal(r.noteInvalidWithoutRequired, 1);
+        assert.equal(r.dlgformSucceeded, false);
+        assert.equal(r.dlgformStillOpen, 1);
+        assert.equal(r.dlgformLoading, false);
+        assert.ok(r.dlgformInvalidNoteShown);
+        assert.equal(r.mismatchPosts, 0);
+        assert.equal(r.mismatchLoading, false, 'spinner must stop on a password mismatch');
+        assert.equal(r.mismatchMessage, 'Die Passwörter stimmen nicht überein');
+        assert.equal(r.afterEditValid, true, 'editing a password field must clear the mismatch error');
+        assert.equal(r.matchPosts, 1);
+    } finally {
+        await browser.close();
+    }
+});

e2e_tests/invoice-provisionperiod.cjs

@@ -0,0 +1,89 @@
+// Run with: node --test e2e_tests/invoice-provisionperiod.cjs
+const { test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const { chromium } = require('playwright');
+
+const root = path.resolve(__dirname, '..');
+const read = (file) => fs.readFileSync(path.join(root, file), 'utf8');
+
+test('service dates and periods survive entry, editing and reopening', async () => {
+    const browser = await chromium.launch({ headless: true,
+        channel: process.env.PLAYWRIGHT_CHANNEL || (process.platform === 'win32' ? 'msedge' : undefined) });
+    try {
+        const page = await browser.newPage({ timezoneId: 'Europe/Berlin' });
+        await page.setContent('<html><body></body></html>');
+        for (const file of [
+            'Fuchs/wwwroot/lib/jquery/jquery.js',
+            'Fuchs/js/intranet/oci_texts_basic_de.js',
+            'Fuchs/js/intranet/oci_basic.js',
+            'Fuchs/js/intranet/oci_mainbase.js',
+            'Fuchs/js/intranet/oci_main.js'
+        ]) {
+            await page.addScriptTag({ content: read(file) });
+        }
+        // Use the production form builder/serializer and dialog submit handler;
+        // only the modal shell and server transport are replaced locally.
+        const source = read('Fuchs/js/intranet/modules/fis.inv_shared.js');
+        await page.addScriptTag({ content: 'var $inv = { d: { sync: function(delta) { window.lastDelta = delta; } } };\n'
+            + source.slice(source.indexOf('$inv.provToIso ='), source.indexOf('/* Main recipient + CC')) });
+        const results = await page.evaluate(() => {
+            let dialog;
+            $ocms.dlg = (content, options) => { dialog = { content, options }; return dialog; };
+            function open(value) {
+                const t = $('<span>').text(value);
+                const changes = [];
+                $inv.eProvisionPeriod({ data: { t, change: (value) => changes.push(value) } });
+                return { t, changes, fields: dialog.content.find('input').map((i, e) => e.value).get() };
+            }
+            const cases = [
+                ['', '2026-10-06', '', '06.10.2026'],
+                ['', '2026-10-01', '2026-10-06', '01.10.2026 - 06.10.2026'],
+                ['18.06.2026', '2026-10-06', '', '06.10.2026'],
+                ['01.06.2026 - 30.06.2026', '2026-10-01', '2026-10-06', '01.10.2026 - 06.10.2026'],
+                ['18.06.2026', '2026-10-01', '2026-10-06', '01.10.2026 - 06.10.2026'],
+                ['01.06.2026 - 30.06.2026', '2026-10-06', '', '06.10.2026'],
+                ['2026-06-18', '2026-10-06', '', '06.10.2026'],
+                ['2026-06-01 - 2026-06-30', '2026-10-01', '2026-10-06', '01.10.2026 - 06.10.2026'],
+                ['18.06.2026', '', '', ''],
+                ['', '2026-10-06', '2026-10-06', '06.10.2026']
+            ];
+            const dates = cases.map(([initial, von, bis, expected]) => {
+                const entry = open(initial);
+                dialog.content.find('[name=von]').val(von);
+                dialog.content.find('[name=bis]').val(bis);
+                dialog.options.confirm.call(dialog.content[0]);
+                const saved = window.lastDelta;
+                return { initial, von, bis, expected, saved, displayed: entry.t.text(), changes: entry.changes,
+                    prefilled: entry.fields, reopened: open(saved.Value).fields };
+            });
+            const optional = $('<div><input name="date" type="date" data-format="date:dd.MM.yyyy;yyyy-MM-dd"></div>');
+            const emptyOptional = optional.serializeObject(true);
+            const emptyOptionalTyped = optional.serializeObject(true, { typedvalues: true });
+            optional.find('input').prop('required', true);
+            const emptyRequired = optional.serializeObject(true);
+            let submitted = false;
+            $ocms.dlgform([{ name: 'date', type: 'date', required: true }], { success: () => { submitted = true; } });
+            dialog.options.confirm.call(dialog.content[0]);
+            return { dates, emptyOptional, emptyOptionalTyped, emptyRequired, submitted };
+        });
+        for (const row of results.dates) {
+            const label = JSON.stringify([row.initial, row.von, row.bis]);
+            assert.deepEqual(row.saved, { Target: 'provisionperiod', Value: row.expected }, label);
+            assert.equal(row.displayed, row.expected, label);
+            assert.deepEqual(row.changes, [row.expected], label);
+            assert.deepEqual(row.reopened, row.von ? [row.von, row.bis === row.von ? '' : row.bis] : ['', ''], label);
+        }
+        assert.deepEqual(results.dates[2].prefilled, ['2026-06-18', '']);
+        assert.deepEqual(results.dates[3].prefilled, ['2026-06-01', '2026-06-30']);
+        assert.deepEqual(results.dates[6].prefilled, ['2026-06-18', '']);
+        assert.deepEqual(results.dates[7].prefilled, ['2026-06-01', '2026-06-30']);
+        assert.deepEqual(results.emptyOptional, { date: '' });
+        assert.deepEqual(results.emptyOptionalTyped, { date: '' });
+        assert.equal(results.emptyRequired, null);
+        assert.equal(results.submitted, false, 'invalid forms must not invoke success and clear existing values');
+    } finally {
+        await browser.close();
+    }
+});