Fix dragging while the text selection toolbar is up doesn't hide toolbar (#106878)

Fixes a fidelity bug on desktop involving the selection toolbar not hiding when it should have.

packages/flutter/lib/src/cupertino/text_field.dart

@@ -969,7 +969,7 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with Restoratio
             || cause == SelectionChangedCause.drag) {
           _editableText.bringIntoView(selection.extent);
         }
-        return;
+        break;
       case TargetPlatform.linux:
       case TargetPlatform.windows:
       case TargetPlatform.fuchsia:
@@ -977,7 +977,21 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with Restoratio
         if (cause == SelectionChangedCause.drag) {
           _editableText.bringIntoView(selection.extent);
         }
-        return;
+        break;
+    }
+
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.iOS:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.android:
+        break;
+      case TargetPlatform.macOS:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        if (cause == SelectionChangedCause.drag) {
+          _editableText.hideToolbar();
+        }
+        break;
     }
   }
 

packages/flutter/lib/src/material/text_field.dart

@@ -1063,7 +1063,7 @@ class _TextFieldState extends State<TextField> with RestorationMixin implements
             || cause == SelectionChangedCause.drag) {
           _editableText?.bringIntoView(selection.extent);
         }
-        return;
+        break;
       case TargetPlatform.linux:
       case TargetPlatform.windows:
       case TargetPlatform.fuchsia:
@@ -1071,7 +1071,21 @@ class _TextFieldState extends State<TextField> with RestorationMixin implements
         if (cause == SelectionChangedCause.drag) {
           _editableText?.bringIntoView(selection.extent);
         }
-        return;
+        break;
+    }
+
+    switch (Theme.of(context).platform) {
+      case TargetPlatform.iOS:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.android:
+        break;
+      case TargetPlatform.macOS:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        if (cause == SelectionChangedCause.drag) {
+          _editableText?.hideToolbar();
+        }
+        break;
     }
   }
 

packages/flutter/test/cupertino/text_field_test.dart

@@ -155,7 +155,6 @@ class PathPointsMatcher extends Matcher {
   }
 }
 
-
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   final MockClipboard mockClipboard = MockClipboard();
@@ -4080,6 +4079,53 @@ void main() {
       expect(find.byType(CupertinoTextSelectionToolbar), findsOneWidget);
       expect(tester.takeException(), null);
     });
+
+    testWidgets('Drag selection hides the selection menu', (WidgetTester tester) async {
+      final TextEditingController controller = TextEditingController(
+        text: 'blah1 blah2',
+      );
+      await tester.pumpWidget(
+        CupertinoApp(
+          home: Center(
+            child: CupertinoTextField(
+              controller: controller,
+            ),
+          ),
+        ),
+      );
+
+      // Initially, the menu is not shown and there is no selection.
+      expect(controller.selection, const TextSelection(baseOffset: -1, extentOffset: -1));
+      final Offset midBlah1 = textOffsetToPosition(tester, 2);
+      final Offset midBlah2 = textOffsetToPosition(tester, 8);
+
+      // Right click the second word.
+      final TestGesture gesture = await tester.startGesture(
+        midBlah2,
+        kind: PointerDeviceKind.mouse,
+        buttons: kSecondaryMouseButton,
+      );
+      await tester.pump();
+      await gesture.up();
+      await tester.pumpAndSettle();
+
+      // The toolbar is shown.
+      expect(find.text('Paste'), findsOneWidget);
+
+      // Drag the mouse to the first word.
+      final TestGesture gesture2 = await tester.startGesture(
+        midBlah1,
+        kind: PointerDeviceKind.mouse,
+      );
+      await tester.pump();
+      await gesture2.moveTo(midBlah2);
+      await tester.pump();
+      await gesture2.up();
+      await tester.pumpAndSettle();
+
+      // The toolbar is hidden.
+      expect(find.text('Paste'), findsNothing);
+    }, variant: TargetPlatformVariant.desktop());
   }, skip: isContextMenuProvidedByPlatform); // [intended] only applies to platforms where we supply the context menu.
 
   group('textAlignVertical position', () {
@@ -4509,6 +4555,7 @@ void main() {
       },
     );
   });
+
   testWidgets("Arrow keys don't move input focus", (WidgetTester tester) async {
     final TextEditingController controller1 = TextEditingController();
     final TextEditingController controller2 = TextEditingController();

packages/flutter/test/material/text_field_test.dart

@@ -7658,6 +7658,56 @@ void main() {
     skip: isContextMenuProvidedByPlatform, // [intended] only applies to platforms where we supply the context menu.,
   );
 
+  testWidgets('Drag selection hides the selection menu', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: 'blah1 blah2',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: TextField(
+            controller: controller,
+          ),
+        ),
+      ),
+    );
+
+    // Initially, the menu is not shown and there is no selection.
+    expect(controller.selection, const TextSelection(baseOffset: -1, extentOffset: -1));
+    final Offset midBlah1 = textOffsetToPosition(tester, 2);
+    final Offset midBlah2 = textOffsetToPosition(tester, 8);
+
+    // Right click the second word.
+    final TestGesture gesture = await tester.startGesture(
+      midBlah2,
+      kind: PointerDeviceKind.mouse,
+      buttons: kSecondaryMouseButton,
+    );
+    await tester.pump();
+    await gesture.up();
+    await tester.pumpAndSettle();
+
+    // The toolbar is shown.
+    expect(find.text('Paste'), findsOneWidget);
+
+    // Drag the mouse to the first word.
+    final TestGesture gesture2 = await tester.startGesture(
+      midBlah1,
+      kind: PointerDeviceKind.mouse,
+    );
+    await tester.pump();
+    await gesture2.moveTo(midBlah2);
+    await tester.pump();
+    await gesture2.up();
+    await tester.pumpAndSettle();
+
+    // The toolbar is hidden.
+    expect(find.text('Paste'), findsNothing);
+  },
+    variant: TargetPlatformVariant.desktop(),
+    skip: isContextMenuProvidedByPlatform, // [intended] only applies to platforms where we supply the context menu.
+  );
+
   testWidgets(
     'Long press on an autofocused field shows the selection menu',
     (WidgetTester tester) async {