Fix verified tap-first Command Dock visual order (WPF sort SSOT, viewport, regression)

MainWindow.xaml

@@ -697,7 +697,7 @@
                                         </Grid.RowDefinitions>
 
                                         <Grid Grid.Row="0" MinHeight="0" ClipToBounds="True">
-                                            <DataGrid x:Name="EquipmentCommandGrid" ItemsSource="{Binding SelectedDevice.CommandSignals}" Loaded="CommandGrid_Loaded" IsReadOnly="False" CanUserAddRows="False" CanUserDeleteRows="False"
+                                            <DataGrid x:Name="EquipmentCommandGrid" ItemsSource="{Binding SelectedDevice.CommandSignals}" Loaded="CommandGrid_Loaded" IsReadOnly="False" CanUserAddRows="False" CanUserDeleteRows="False" CanUserSortColumns="False"
                                                       Style="{StaticResource CommandDataGrid}" RowStyle="{StaticResource CommandDataGridRow}"
                                                       CellStyle="{StaticResource CommandDataGridCell}" ColumnHeaderStyle="{StaticResource CommandDataGridHeader}"
                                                       AutoGenerateColumns="False" MinHeight="56" RowHeight="43" MinRowHeight="42" ColumnHeaderHeight="35" FrozenColumnCount="1"

MainWindow.xaml.cs

@@ -129,6 +129,10 @@ public Iec61850MonitorDevice? SelectedDevice
             Raise(nameof(ActiveIedSubtitle));
             RaiseWorkspaceCounts();
             TryAutoExpandCommandPanelOnce(_selectedDevice);
+            // The persistent Dock may retain the previous IED's viewport.
+            // Reposition once on real IED selection, never on report ingress.
+            if (CommandPanelExpander?.IsExpanded == true)
+                ScrollVerifiedEquipmentCommandsIntoView();
             ApplyExplorerLiveSearchFilter();
             if (MainTabs?.SelectedIndex == IedBrowserWorkspaceIndex)
                 RefreshIedBrowser();
@@ -1475,9 +1479,17 @@ private void ScrollVerifiedEquipmentCommandsIntoView()
         Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Loaded,
             new Action(() =>
             {
-                if (ReferenceEquals(SelectedDevice, device) &&
-                    device.CommandSignals.Contains(first))
-                    EquipmentCommandGrid.ScrollIntoView(first);
+                if (!ReferenceEquals(SelectedDevice, device) ||
+                    !device.CommandSignals.Contains(first))
+                    return;
+
+                // ScrollIntoView alone only ensures visibility, so a Tap
+                // already visible on the LAST row would remain at the bottom.
+                // Reset the virtualized viewport on expand/device switch only.
+                if (EquipmentCommandGrid.Template?.FindName(
+                        "DG_ScrollViewer", EquipmentCommandGrid) is ScrollViewer scroll)
+                    scroll.ScrollToTop();
+                EquipmentCommandGrid.ScrollIntoView(first);
             }));
     }
 

Services/IecNaturalReferenceOrder.cs

@@ -66,15 +66,12 @@ public int Compare(object? a, object? b)
         if (ReferenceEquals(a, b)) return 0;
         if (a is not SignalDefinition left || b is not SignalDefinition right)
             return Comparer.DefaultInvariant.Compare(a,b);
-        // WPF's ListCollectionView.CustomSort is the FINAL visual order.
-        // The underlying device.OperableCommandSignals is already ranked,
-        // but the view's alphabetical comparer used to override that rank:
-        // SG7_BCUMaster/GGIO2 sorted above SG7_BCUSystem/Bkr0XCBR.Pos.
-        // Match exactly the live-verified command role priority at the view
-        // boundary, while keeping natural instance order WITHIN each role.
-        // This is presentation only; no rank authorizes an MMS Operate.
-        var role = Iec61850ControlIdentity.CommandDockPriority(left)
-            .CompareTo(Iec61850ControlIdentity.CommandDockPriority(right));
+        // WPF CustomSort is the final visible order (not CommandSignals).
+        // Use the SAME presentation-only priority as the source projection;
+        // the former role-only sorter put StatusOnly CSWI above verified BSC
+        // tap control. Live ctlModel/CDC admission remains independent.
+        var role = Iec61850ControlIdentity.CommandDockDisplayPriority(left)
+            .CompareTo(Iec61850ControlIdentity.CommandDockDisplayPriority(right));
         if (role != 0) return role;
         var result = IecNaturalReferenceOrder.Compare(left.DisplayReference,right.DisplayReference);
         return result != 0 ? result : IecNaturalReferenceOrder.Compare(left.ObjectReference,right.ObjectReference);

tests/ARSAS.Tests/MultiGridNaturalSortRegressionTests.cs

@@ -132,6 +132,91 @@ static SignalDefinition Verified(string reference, string cdc = "DPC")
         });
     }
 
+    [Fact]
+    public void RealWpfZivDockShowsLiveTapBeforeFourStatusOnlyCswi_WithoutSourceMutation()
+    {
+        RunInSta(() =>
+        {
+            static SignalDefinition Control(string reference, string cdc, string model, bool verified)
+            {
+                var signal = new SignalDefinition
+                {
+                    Name = reference,
+                    ObjectReference = reference,
+                    IsControlSignal = true,
+                    IsSelected = true,
+                    HasControlServiceEvidence = true,
+                    FunctionalConstraint = "CO",
+                    ControlCdc = cdc,
+                    ControlModelText = model
+                };
+                if (verified)
+                {
+                    signal.AcceptVerifiedLiveControlCdc(cdc);
+                    signal.ControlSemanticVerified = true;
+                }
+                return signal;
+            }
+            var tap = Control("ZIVAVRLD1/ATCC1.TapChg", "BSC",
+                "Select Before Operate (SBO) • Normal security", true);
+            var cswi = Enumerable.Range(1, 4)
+                .Select(i => Control($"ZIVAVRLD1/CSWI{i}.Pos", "DPC", "Status only", false))
+                .ToArray();
+            var device = new Iec61850MonitorDevice();
+            device.Signals.ReplaceAll([..cswi, tap]);
+            device.RecountSelectedSignals();
+            Assert.True(tap.ControlSupportsOperate);
+            Assert.All(cswi, s => Assert.False(s.ControlSupportsOperate));
+            Assert.Same(tap, device.CommandSignals[0]);
+
+            // This is the actual WPF collection view that painted the
+            // reported field screenshot incorrectly despite source order.
+            var grid = new DataGrid
+            {
+                CanUserAddRows = false, CanUserDeleteRows = false,
+                CanUserSortColumns = false, ItemsSource = device.CommandSignals
+            };
+            var view = Assert.IsType<ListCollectionView>(
+                CollectionViewSource.GetDefaultView(grid.ItemsSource));
+            view.SortDescriptions.Clear();
+            view.CustomSort = IecNaturalCommandSort.Instance;
+            SignalDefinition[] Visual() => view.Cast<SignalDefinition>().ToArray();
+
+            Assert.Same(tap, Visual()[0]);
+            Assert.Equal(cswi, Visual().Skip(1));
+            Assert.Equal(5, Visual().Length);
+
+            // Report/value churn must not recycle rows or elevate read-only
+            // controls. Changing process values never changes ctlModel.
+            var changes = 0;
+            device.CommandSignals.CollectionChanged += (_, _) => changes++;
+            for (var i = 0; i < 100; ++i)
+            {
+                tap.ControlCurrentValue = (i % 2 + 1).ToString();
+                device.RefreshCommandSignalProjection();
+            }
+            Assert.Equal(0, changes);
+            Assert.Same(tap, Visual()[0]);
+            Assert.All(Visual().Skip(1), s => Assert.False(s.ControlSupportsOperate));
+        });
+    }
+
+    [Fact]
+    public void CommandGridForbidsHeaderSortingAndResetsViewportOnIedSwitch()
+    {
+        var xaml = Read("MainWindow.xaml");
+        var xml = XDocument.Parse(xaml);
+        XNamespace wpf = "http://schemas.microsoft.com/winfx/2006/xaml/presentation";
+        XNamespace x = "http://schemas.microsoft.com/winfx/2006/xaml";
+        var command = xml.Descendants(wpf + "DataGrid")
+            .Single(g => (string?)g.Attribute(x + "Name") == "EquipmentCommandGrid");
+        Assert.Equal("False", (string?)command.Attribute("CanUserSortColumns"));
+
+        var code = Read("MainWindow.xaml.cs");
+        Assert.Contains("ScrollVerifiedEquipmentCommandsIntoView();", code);
+        Assert.Contains("scroll.ScrollToTop();", code);
+    }
+
     [Fact]
     public void CommandComparatorDoesNotTreatUnverifiedNamesAsOperatePermission()
     {