mixin_markdown_widget: let MixinSelectionArea settle with MarkdownWidget

packages/mixin_markdown_widget/lib/src/render/markdown_document_view.dart

@@ -174,7 +174,11 @@ class _MarkdownDocumentViewState extends State<MarkdownDocumentView> {
         oldWidget.selectable != widget.selectable) {
       _cachedBlockRows.clear();
     }
-    _syncSelectionParticipant(participantChanged: true);
+    // Only notify on document changes: the registrar's refresh rebuilds this
+    // widget, so an unconditional notification never lets frames settle.
+    _syncSelectionParticipant(
+      participantChanged: !identical(oldWidget.document, widget.document),
+    );
   }
 
   @override

packages/mixin_markdown_widget/test/markdown_context_menu_test.dart

@@ -33,21 +33,13 @@ Offset _characterCenter(
   return renderBox.localToGlobal(box.center);
 }
 
-Future<void> _rightClick(
-  WidgetTester tester,
-  Offset position, {
-  bool settle = true,
-}) async {
+Future<void> _rightClick(WidgetTester tester, Offset position) async {
   await tester.tapAt(
     position,
     buttons: kSecondaryMouseButton,
     kind: PointerDeviceKind.mouse,
   );
-  if (settle) {
-    await tester.pumpAndSettle();
-  } else {
-    await tester.pump();
-  }
+  await tester.pumpAndSettle();
 }
 
 Future<void> _doubleClick(WidgetTester tester, Offset position) async {
@@ -166,12 +158,10 @@ void main() {
           ),
         );
 
-        await tester.pump();
+        await tester.pumpAndSettle();
         await _rightClick(
           tester,
           _characterCenter(tester, containing: 'Hello', character: 'v'),
-          // MixinSelectionArea keeps scheduling frames, so it never settles.
-          settle: false,
         );
         expect(selection.selectedPlainText, 'brave');
         expect(_menu, findsOneWidget);

packages/mixin_markdown_widget/test/mixin_markdown_widget_test.dart

@@ -7878,6 +7878,36 @@ Tables support varying alignments, complex cell contents, and inline styles.
     expect(selectionRects, isNotEmpty);
   });
 
+  testWidgets('MixinSelectionArea with MarkdownWidget settles', (tester) async {
+    final selectionController = MarkdownSelectionController();
+    addTearDown(selectionController.dispose);
+
+    Widget buildApp(String data) {
+      return MaterialApp(
+        home: Scaffold(
+          body: MixinSelectionArea(
+            controller: selectionController,
+            child: MarkdownWidget(data: data, useColumn: true),
+          ),
+        ),
+      );
+    }
+
+    await tester.pumpWidget(buildApp('Hello brave world'));
+    await tester.pumpAndSettle();
+
+    expect(tester.binding.hasScheduledFrame, isFalse);
+    selectionController.selectAll();
+    expect(selectionController.selectedPlainText, 'Hello brave world');
+
+    await tester.pumpWidget(buildApp('Hello new world'));
+    await tester.pumpAndSettle();
+
+    expect(tester.binding.hasScheduledFrame, isFalse);
+    selectionController.selectAll();
+    expect(selectionController.selectedPlainText, 'Hello new world');
+  });
+
   testWidgets('MixinSelectionArea exposes public selectable widgets',
       (tester) async {
     final selectionController = MarkdownSelectionController();