MouseRegion enter/exit event can be triggered with button pressed (#81148)

packages/flutter/lib/src/rendering/binding.dart

@@ -282,7 +282,13 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
         event is PointerAddedEvent ||
         event is PointerRemovedEvent) {
       assert(event.position != null);
-      _mouseTracker!.updateWithEvent(event, () => hitTestResult ?? renderView.hitTestMouseTrackers(event.position));
+      _mouseTracker!.updateWithEvent(
+        event,
+        // Mouse events(enter and exit) can be triggered with or without buttons pressed.
+        // If the button is pressed, we need to re-execute the hit test instead of
+        // reusing the cached results to trigger possible events.
+        () => (hitTestResult == null || event.down) ? renderView.hitTestMouseTrackers(event.position) : hitTestResult,
+      );
     }
     super.dispatchEvent(event, hitTestResult);
   }

packages/flutter/test/widgets/mouse_region_test.dart

@@ -76,6 +76,42 @@ class _HoverFeedbackState extends State<HoverFeedback> {
 }
 
 void main() {
+  testWidgets('onEnter and onExit can be triggered with mouse buttons pressed', (WidgetTester tester) async {
+    PointerEnterEvent? enter;
+    PointerExitEvent? exit;
+    await tester.pumpWidget(Center(
+      child: MouseRegion(
+        child: Container(
+          color: const Color.fromARGB(0xff, 0xff, 0x00, 0x00),
+          width: 100.0,
+          height: 100.0,
+        ),
+        onEnter: (PointerEnterEvent details) => enter = details,
+        onExit: (PointerExitEvent details) => exit = details,
+      ),
+    ));
+
+    final TestGesture gesture = await tester.createGesture(kind: PointerDeviceKind.mouse, buttons: kPrimaryMouseButton);
+    await gesture.addPointer(location: Offset.zero);
+    await gesture.down(Offset.zero); // Press the mouse button.
+    addTearDown(gesture.removePointer);
+    await tester.pump();
+    enter = null;
+    exit = null;
+    // Trigger the enter event.
+    await gesture.moveTo(const Offset(400.0, 300.0));
+    expect(enter, isNotNull);
+    expect(enter!.position, equals(const Offset(400.0, 300.0)));
+    expect(enter!.localPosition, equals(const Offset(50.0, 50.0)));
+    expect(exit, isNull);
+
+    // Trigger the exit event.
+    await gesture.moveTo(const Offset(1.0, 1.0));
+    expect(exit, isNotNull);
+    expect(exit!.position, equals(const Offset(1.0, 1.0)));
+    expect(exit!.localPosition, equals(const Offset(-349.0, -249.0)));
+  });
+
   testWidgets('detects pointer enter', (WidgetTester tester) async {
     PointerEnterEvent? enter;
     PointerHoverEvent? move;