fix(ui): expose source and inject native pointer movement

Declare the native source surface before the embedded browser without changing its visual column. Replace cursor-only warping with checked SendInput movement after hosted traces showed drag start/completion without deltas; retain physical mode and resize assertions and add source-divider acceptance.

Refs: #8, #9, #10

Co-Authored-By: Codex (GPT-6) <noreply@openai.com>
Signed-off-by: James Maes <jmaes@dmdbrands.com>

docs/SESSION-STATE.md

@@ -120,3 +120,25 @@ Fixture-only MARKDOWNVIEWR_INPUT_TRACE=1 records native pressed/released/capture
 outline drag events and frontmatter clicks without changing routing or logging content.
 This tests whether WinUI receives the exact physical events; no third timing workaround
 or weakened outcome assertion. The next exact hosted handles must be observed.
+
+## Native events captured and movement correction
+
+9ff820f4773c54573c1d24028ba489328bf2e9c6 CI 38106466328 loose native/UI
+finished 31/34: two prior input failures plus SourceText accessibility lookup.
+Build/format/scripts/security/CodeQL passed; installed producer now terminal FAILURE.
+Retained exact log: artifacts/native-event-source-ui-38106466328.log.
+
+Trace shows Markdown press handled and release unhandled with no click. Outline
+DragStarted and DragCompleted occur, but no DragDelta. The pinned FlaUI 5.0.0
+Mouse.Position/MoveTo implementation uses SetCursorPos, while Down/Up use SendInput.
+Follow-up injects a real absolute MOUSEEVENTF_MOVE through the existing FlaUI Win32
+API, with virtual-desktop bounds/normalization and failure checks. Button states,
+exact target checks, 70-pixel resize and all saved-mode/width assertions remain.
+Entered/exited/outline-moved traces will distinguish the next delivery path.
+
+Declare native source controls before WebView2 while retaining Grid.Column positions,
+as the earlier verified StatusText accessibility fix did. Source test now includes a
+real 70-pixel source-divider drag; normalize only native line-ending presentation.
+Source/outline resize and frontmatter remain unverified until exact hosted results.
+All 9ff820f producers are now terminal; the follow-up may be pushed without cancelling them.
+Native paired-find research retained in artifacts/native-find-notes.md; full scope active.

src/MarkdownViewr.Windows/MainWindow.InputDiagnostics.cs

@@ -21,10 +21,13 @@ public sealed partial class MainWindow
       }
       foreach(UIElement element in new UIElement[] { RootGrid, OutlineDivider, SourceDivider, FrontmatterHide, FrontmatterMetadata, FrontmatterMarkdown })
       {
+         element.AddHandler(UIElement.PointerEnteredEvent, new PointerEventHandler((sender, args) => TracePointer("entered", sender, args)), handledEventsToo: true);
+         element.AddHandler(UIElement.PointerExitedEvent, new PointerEventHandler((sender, args) => TracePointer("exited", sender, args)), handledEventsToo: true);
          element.AddHandler(UIElement.PointerPressedEvent, new PointerEventHandler((sender, args) => TracePointer("pressed", sender, args)), handledEventsToo: true);
          element.AddHandler(UIElement.PointerReleasedEvent, new PointerEventHandler((sender, args) => TracePointer("released", sender, args)), handledEventsToo: true);
          element.AddHandler(UIElement.PointerCaptureLostEvent, new PointerEventHandler((sender, args) => TracePointer("capture-lost", sender, args)), handledEventsToo: true);
       }
+      OutlineDivider.AddHandler(UIElement.PointerMovedEvent, new PointerEventHandler((sender, args) => TracePointer("moved", sender, args)), handledEventsToo: true);
       OutlineDivider.DragStarted += (_, args) => App.Log.Info(FormattableString.Invariant($"Input trace: outline drag started; x={args.HorizontalOffset}; y={args.VerticalOffset}."));
       OutlineDivider.DragDelta += (_, args) => App.Log.Info(FormattableString.Invariant($"Input trace: outline drag delta; x={args.HorizontalChange}; y={args.VerticalChange}."));
       OutlineDivider.DragCompleted += (_, args) => App.Log.Info(FormattableString.Invariant($"Input trace: outline drag completed; canceled={args.Canceled}."));

src/MarkdownViewr.Windows/MainWindow.xaml

@@ -96,7 +96,6 @@
                </ControlTemplate>
             </primitives:Thumb.Template>
          </primitives:Thumb>
-         <WebView2 x:Name="DocumentView" Grid.Column="2" Loaded="DocumentView_Loaded" AutomationProperties.Name="Markdown document" />
          <primitives:Thumb x:Name="SourceDivider" Grid.Column="3" Background="{ThemeResource DividerStrokeColorDefaultBrush}" DragDelta="SourceDivider_DragDelta" DragCompleted="SourceDivider_DragCompleted" AutomationProperties.Name="Resize Markdown source">
             <primitives:Thumb.Template>
                <ControlTemplate TargetType="primitives:Thumb">
@@ -105,6 +104,7 @@
             </primitives:Thumb.Template>
          </primitives:Thumb>
          <TextBox x:Name="SourceText" Grid.Column="4" Visibility="Collapsed" IsReadOnly="True" AcceptsReturn="True" TextWrapping="NoWrap" FontFamily="Consolas" Padding="12" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" AutomationProperties.Name="Markdown source" />
+         <WebView2 x:Name="DocumentView" Grid.Column="2" Loaded="DocumentView_Loaded" AutomationProperties.Name="Markdown document" />
       </Grid>
    </Grid>
 </Window>

tests/MarkdownViewr.Windows.UiTests/AppSession.cs

@@ -255,7 +255,7 @@ public sealed class AppSession : IDisposable
       {
          throw new InvalidOperationException("The native mouse target no longer has a clickable point.");
       }
-      Mouse.Position = point;
+      NativeMouse.MoveTo(point);
       Wait.UntilInputIsProcessed();
       AutomationElement? hit = Automation.FromPoint(Mouse.Position);
       for(int depth = 0; hit is not null && depth < 8; depth++, hit = hit.Parent)

tests/MarkdownViewr.Windows.UiTests/AppTests.cs

@@ -215,9 +215,17 @@ public class AppTests
       session.WaitFor(() => session.FindInApp(cf => cf.ByName("Source acceptance")), "the document heading", TimeSpan.FromSeconds(30));
       Assert.Null(session.FindInApp(cf => cf.ByAutomationId("SourceText")));
       session.InvokeMenuItem("View", "SourceToggle");
-      AutomationElement source = session.WaitForElement("SourceText");
+      AutomationElement source;
+      try
+      {
+         source = session.WaitForElement("SourceText");
+      }
+      catch(TimeoutException exception)
+      {
+         throw new TimeoutException($"{exception.Message} Settings: {session.ReadSettings()} Logs: {session.ReadLogs()} Native tree: {session.DescribeDocumentStatus()}", exception);
+      }
       Assert.True(source.Patterns.Value.Pattern.IsReadOnly.Value);
-      string value = source.Patterns.Value.Pattern.Value.Value.Replace("\r\n", "\n", StringComparison.Ordinal);
+      string value = source.Patterns.Value.Pattern.Value.Value.ReplaceLineEndings("\n");
       Assert.Equal(Markdown, value);
       using(var settings = JsonDocument.Parse(session.ReadSettings()))
       {
@@ -227,6 +235,25 @@ public class AppTests
       File.WriteAllText(Path.Combine(session.DataDirectory, "document.md"), "# Source replacement\n\n**New literal text**");
       session.WaitFor(() => source.Patterns.Value.Pattern.Value.Value.Contains("**New literal text**", StringComparison.Ordinal) ? source : null, "the source snapshot after reload");
       session.WaitFor(() => session.FindInApp(cf => cf.ByName("Source replacement")), "the rendered replacement heading");
+      AutomationElement divider = session.WaitForElement("SourceDivider");
+      session.MainWindow.SetForeground();
+      Assert.True(divider.TryGetClickablePoint(out System.Drawing.Point start));
+      Assert.Equal("SourceDivider", session.Automation.FromPoint(start).Properties.AutomationId.ValueOrDefault);
+      NativeMouse.MoveTo(start);
+      FlaUI.Core.Input.Wait.UntilInputIsProcessed();
+      FlaUI.Core.Input.Mouse.Down(FlaUI.Core.Input.MouseButton.Left);
+      FlaUI.Core.Input.Wait.UntilInputIsProcessed();
+      NativeMouse.MoveTo(new System.Drawing.Point(start.X - 70, start.Y));
+      FlaUI.Core.Input.Wait.UntilInputIsProcessed();
+      FlaUI.Core.Input.Mouse.Up(FlaUI.Core.Input.MouseButton.Left);
+      FlaUI.Core.Input.Wait.UntilInputIsProcessed();
+      session.WaitFor(
+         () =>
+         {
+            using var settings = JsonDocument.Parse(session.ReadSettings());
+            return settings.RootElement.GetProperty("SourceWidth").GetDouble() > 360 ? session.MainWindow : null;
+         },
+         "the physically resized source width to be saved");
       session.InvokeMenuItem("View", "SourceToggle");
       session.WaitForElementGone("SourceText");
       using var hidden = JsonDocument.Parse(session.ReadSettings());
@@ -254,11 +281,11 @@ public class AppTests
       Assert.True(divider.TryGetClickablePoint(out System.Drawing.Point start));
       Assert.Equal(session.App.ProcessId, session.Automation.FromPoint(start).Properties.ProcessId.ValueOrDefault);
       Assert.Equal("OutlineDivider", session.Automation.FromPoint(start).Properties.AutomationId.ValueOrDefault);
-      FlaUI.Core.Input.Mouse.Position = start;
+      NativeMouse.MoveTo(start);
       FlaUI.Core.Input.Wait.UntilInputIsProcessed();
       FlaUI.Core.Input.Mouse.Down(FlaUI.Core.Input.MouseButton.Left);
       FlaUI.Core.Input.Wait.UntilInputIsProcessed();
-      FlaUI.Core.Input.Mouse.MoveTo(new System.Drawing.Point(start.X + 70, start.Y));
+      NativeMouse.MoveTo(new System.Drawing.Point(start.X + 70, start.Y));
       FlaUI.Core.Input.Wait.UntilInputIsProcessed();
       FlaUI.Core.Input.Mouse.Up(FlaUI.Core.Input.MouseButton.Left);
       FlaUI.Core.Input.Wait.UntilInputIsProcessed();

tests/MarkdownViewr.Windows.UiTests/NativeMouse.cs

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2026 James Maes
+ * SPDX-License-Identifier: MIT
+ */
+
+using System.ComponentModel;
+using System.Drawing;
+using System.Runtime.InteropServices;
+using FlaUI.Core.WindowsAPI;
+
+
+namespace MarkdownViewr.Windows.UiTests;
+
+/// <summary>Injects pointer movement through the same Windows input queue used for button events.</summary>
+internal static class NativeMouse
+{
+   /// <summary>Uses absolute virtual-desktop coordinates; cursor warping alone did not deliver outline movement in hosted traces.</summary>
+   public static void MoveTo(Point point)
+   {
+      int left = User32.GetSystemMetrics(SystemMetric.SM_XVIRTUALSCREEN);
+      int top = User32.GetSystemMetrics(SystemMetric.SM_YVIRTUALSCREEN);
+      int width = User32.GetSystemMetrics(SystemMetric.SM_CXVIRTUALSCREEN);
+      int height = User32.GetSystemMetrics(SystemMetric.SM_CYVIRTUALSCREEN);
+      if(width <= 0 || height <= 0 || point.X < left || point.X >= left + width || point.Y < top || point.Y >= top + height)
+      {
+         throw new InvalidOperationException("The native mouse target is outside the virtual desktop.");
+      }
+      var mouse = new MOUSEINPUT
+      {
+         dx = (int)(((long)(point.X - left) * 65536 + 32768) / width),
+         dy = (int)(((long)(point.Y - top) * 65536 + 32768) / height),
+         dwFlags = MouseEventFlags.MOUSEEVENTF_MOVE | MouseEventFlags.MOUSEEVENTF_ABSOLUTE | MouseEventFlags.MOUSEEVENTF_VIRTUALDESK,
+      };
+      var input = INPUT.MouseInput(mouse);
+      if(User32.SendInput(1, [input], INPUT.Size) != 1)
+      {
+         throw new Win32Exception(Marshal.GetLastWin32Error(), "Windows did not accept the native mouse move.");
+      }
+   }
+}