Implement SelectionArea single click/tap gestures (#132682)

This change collapses the selection at the clicked/tapped location on single click down for desktop platforms, and on single click/tap up for mobile platforms to match native.

This is a change from how `SelectionArea` previously worked. Before this change a single click down would clear the selection. From observing a native browser it looks like when tapping on static text the selection is not cleared but collapsed. A user can still attain the selection from static text using the `window.getSelection` API.

https://jsfiddle.net/juepasn3/11/ You can try this demo out here to observe this behavior yourself. When clicking on static text the selection will change.

This change also allows `Paragraph.selections` to return selections that are collapsed. This for testing purposes to confirm where the selection has been collapsed.

Partially fixes: #129583

examples/api/test/material/context_menu/selectable_region_toolbar_builder.0_test.dart

@@ -24,6 +24,9 @@ void main() {
 
     // Right clicking the Text in the SelectionArea shows the custom context
     // menu.
+    final TestGesture primaryMouseButtonGesture = await tester.createGesture(
+      kind: PointerDeviceKind.mouse,
+    );
     final TestGesture gesture = await tester.startGesture(
       tester.getCenter(find.text(example.text)),
       kind: PointerDeviceKind.mouse,
@@ -37,7 +40,9 @@ void main() {
     expect(find.text('Print'), findsOneWidget);
 
     // Tap to dismiss.
-    await tester.tapAt(tester.getCenter(find.byType(Scaffold)));
+    await primaryMouseButtonGesture.down(tester.getCenter(find.byType(Scaffold)));
+    await tester.pump();
+    await primaryMouseButtonGesture.up();
     await tester.pumpAndSettle();
 
     expect(find.byType(AdaptiveTextSelectionToolbar), findsNothing);

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

@@ -132,7 +132,7 @@ mixin RenderInlineChildrenContainerDefaults on RenderBox, ContainerRenderObjectM
             ui.PlaceholderAlignment.belowBaseline ||
             ui.PlaceholderAlignment.bottom ||
             ui.PlaceholderAlignment.middle ||
-            ui.PlaceholderAlignment.top      => null,
+            ui.PlaceholderAlignment.top => null,
             ui.PlaceholderAlignment.baseline => child.getDistanceToBaseline(span.baseline!),
           },
         );
@@ -351,8 +351,7 @@ class RenderParagraph extends RenderBox with ContainerRenderObjectMixin<RenderBo
     final List<TextSelection> results = <TextSelection>[];
     for (final _SelectableFragment fragment in _lastSelectableFragments!) {
       if (fragment._textSelectionStart != null &&
-          fragment._textSelectionEnd != null &&
+          fragment._textSelectionEnd != null) {
-          fragment._textSelectionStart!.offset != fragment._textSelectionEnd!.offset) {
         results.add(
           TextSelection(
             baseOffset: fragment._textSelectionStart!.offset,
@@ -1309,9 +1308,9 @@ class RenderParagraph extends RenderBox with ContainerRenderObjectMixin<RenderBo
 
 /// A continuous, selectable piece of paragraph.
 ///
-/// Since the selections in [PlaceHolderSpan] are handled independently in its
+/// Since the selections in [PlaceholderSpan] are handled independently in its
 /// subtree, a selection in [RenderParagraph] can't continue across a
-/// [PlaceHolderSpan]. The [RenderParagraph] splits itself on [PlaceHolderSpan]
+/// [PlaceholderSpan]. The [RenderParagraph] splits itself on [PlaceholderSpan]
 /// to create multiple `_SelectableFragment`s so that they can be selected
 /// separately.
 class _SelectableFragment with Selectable, ChangeNotifier implements TextLayoutMetrics {
@@ -1720,7 +1719,7 @@ class _SelectableFragment with Selectable, ChangeNotifier implements TextLayoutM
     _selectableContainsOriginWord = true;
 
     final TextPosition position = paragraph.getPositionForOffset(paragraph.globalToLocal(globalPosition));
-    if (_positionIsWithinCurrentSelection(position)) {
+    if (_positionIsWithinCurrentSelection(position) && _textSelectionStart != _textSelectionEnd) {
       return SelectionResult.end;
     }
     final _WordBoundaryRecord wordBoundary = _getWordBoundaryAtPosition(position);

packages/flutter/lib/src/widgets/scrollable.dart

@@ -670,7 +670,7 @@ class ScrollableState extends State<Scrollable> with TickerProviderStateMixin, R
       if (oldWidget.controller == null) {
         // The old controller was null, meaning the fallback cannot be null.
         // Dispose of the fallback.
-        assert(_fallbackScrollController !=  null);
+        assert(_fallbackScrollController != null);
         assert(widget.controller != null);
         _fallbackScrollController!.detach(position);
         _fallbackScrollController!.dispose();
@@ -1954,7 +1954,7 @@ class TwoDimensionalScrollableState extends State<TwoDimensionalScrollable> {
       if (oldWidget.horizontalDetails.controller == null) {
         // The old controller was null, meaning the fallback cannot be null.
         // Dispose of the fallback.
-        assert(_horizontalFallbackController !=  null);
+        assert(_horizontalFallbackController != null);
         assert(widget.horizontalDetails.controller != null);
         _horizontalFallbackController!.dispose();
         _horizontalFallbackController = null;

packages/flutter/lib/src/widgets/selectable_region.dart

@@ -352,7 +352,8 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
               _showToolbar(location: details.globalPosition);
             }
           } else {
-            _clearSelection();
+            hideToolbar();
+            _collapseSelectionAt(offset: details.globalPosition);
           }
         };
         instance.onSecondaryTapDown = _handleRightClickDown;
@@ -472,6 +473,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
           (TapAndPanGestureRecognizer instance) {
         instance
           ..onTapDown = _startNewMouseSelectionGesture
+          ..onTapUp = _handleMouseTapUp
           ..onDragStart = _handleMouseDragStart
           ..onDragUpdate = _handleMouseDragUpdate
           ..onDragEnd = _handleMouseDragEnd
@@ -498,7 +500,17 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
       case 1:
         widget.focusNode.requestFocus();
         hideToolbar();
-        _clearSelection();
+        switch (defaultTargetPlatform) {
+          case TargetPlatform.android:
+          case TargetPlatform.fuchsia:
+          case TargetPlatform.iOS:
+            // On mobile platforms the selection is set on tap up.
+            break;
+          case TargetPlatform.macOS:
+          case TargetPlatform.linux:
+          case TargetPlatform.windows:
+            _collapseSelectionAt(offset: details.globalPosition);
+        }
       case 2:
         _selectWordAt(offset: details.globalPosition);
     }
@@ -528,6 +540,24 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
     _updateSelectedContentIfNeeded();
   }
 
+  void _handleMouseTapUp(TapDragUpDetails details) {
+    switch (_getEffectiveConsecutiveTapCount(details.consecutiveTapCount)) {
+      case 1:
+        switch (defaultTargetPlatform) {
+          case TargetPlatform.android:
+          case TargetPlatform.fuchsia:
+          case TargetPlatform.iOS:
+            _collapseSelectionAt(offset: details.globalPosition);
+          case TargetPlatform.macOS:
+          case TargetPlatform.linux:
+          case TargetPlatform.windows:
+            // On desktop platforms the selection is set on tap down.
+            break;
+        }
+    }
+    _updateSelectedContentIfNeeded();
+  }
+
   void _updateSelectedContentIfNeeded() {
     if (_lastSelectedContent?.plainText != _selectable?.getSelectedContent()?.plainText) {
       _lastSelectedContent = _selectable?.getSelectedContent();
@@ -586,8 +616,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
         // keep the current selection, if not then collapse it.
         final bool lastSecondaryTapDownPositionWasOnActiveSelection = _positionIsOnActiveSelection(globalPosition: details.globalPosition);
         if (!lastSecondaryTapDownPositionWasOnActiveSelection) {
-          _selectStartTo(offset: lastSecondaryTapDownPosition!);
+          _collapseSelectionAt(offset: lastSecondaryTapDownPosition!);
-          _selectEndTo(offset: lastSecondaryTapDownPosition!);
         }
         _showHandles();
         _showToolbar(location: lastSecondaryTapDownPosition);
@@ -612,8 +641,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
         // keep the current selection, if not then collapse it.
         final bool lastSecondaryTapDownPositionWasOnActiveSelection = _positionIsOnActiveSelection(globalPosition: details.globalPosition);
         if (!lastSecondaryTapDownPositionWasOnActiveSelection) {
-          _selectStartTo(offset: lastSecondaryTapDownPosition!);
+          _collapseSelectionAt(offset: lastSecondaryTapDownPosition!);
-          _selectEndTo(offset: lastSecondaryTapDownPosition!);
         }
         _showHandles();
         _showToolbar(location: lastSecondaryTapDownPosition);
@@ -925,8 +953,9 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
   /// See also:
   ///  * [_selectStartTo], which sets or updates selection start edge.
   ///  * [_finalizeSelection], which stops the `continuous` updates.
-  ///  * [_clearSelection], which clear the ongoing selection.
+  ///  * [_clearSelection], which clears the ongoing selection.
   ///  * [_selectWordAt], which selects a whole word at the location.
+  ///  * [_collapseSelectionAt], which collapses the selection at the location.
   ///  * [selectAll], which selects the entire content.
   void _selectEndTo({required Offset offset, bool continuous = false, TextGranularity? textGranularity}) {
     if (!continuous) {
@@ -964,8 +993,9 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
   /// See also:
   ///  * [_selectEndTo], which sets or updates selection end edge.
   ///  * [_finalizeSelection], which stops the `continuous` updates.
-  ///  * [_clearSelection], which clear the ongoing selection.
+  ///  * [_clearSelection], which clears the ongoing selection.
   ///  * [_selectWordAt], which selects a whole word at the location.
+  ///  * [_collapseSelectionAt], which collapses the selection at the location.
   ///  * [selectAll], which selects the entire content.
   void _selectStartTo({required Offset offset, bool continuous = false, TextGranularity? textGranularity}) {
     if (!continuous) {
@@ -978,6 +1008,20 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
     }
   }
 
+  /// Collapses the selection at the given `offset` location.
+  ///
+  /// See also:
+  ///  * [_selectStartTo], which sets or updates selection start edge.
+  ///  * [_selectEndTo], which sets or updates selection end edge.
+  ///  * [_finalizeSelection], which stops the `continuous` updates.
+  ///  * [_clearSelection], which clears the ongoing selection.
+  ///  * [_selectWordAt], which selects a whole word at the location.
+  ///  * [selectAll], which selects the entire content.
+  void _collapseSelectionAt({required Offset offset}) {
+    _selectStartTo(offset: offset);
+    _selectEndTo(offset: offset);
+  }
+
   /// Selects a whole word at the `offset` location.
   ///
   /// If the whole word is already in the current selection, selection won't
@@ -991,7 +1035,8 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
   ///  * [_selectStartTo], which sets or updates selection start edge.
   ///  * [_selectEndTo], which sets or updates selection end edge.
   ///  * [_finalizeSelection], which stops the `continuous` updates.
-  ///  * [_clearSelection], which clear the ongoing selection.
+  ///  * [_clearSelection], which clears the ongoing selection.
+  ///  * [_collapseSelectionAt], which collapses the selection at the location.
   ///  * [selectAll], which selects the entire content.
   void _selectWordAt({required Offset offset}) {
     // There may be other selection ongoing.
@@ -1881,7 +1926,7 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
 
     SelectionPoint? startPoint;
     if (startGeometry.startSelectionPoint != null) {
-      final Matrix4 startTransform =  getTransformFrom(selectables[startIndexWalker]);
+      final Matrix4 startTransform = getTransformFrom(selectables[startIndexWalker]);
       final Offset start = MatrixUtils.transformPoint(startTransform, startGeometry.startSelectionPoint!.localPosition);
       // It can be NaN if it is detached or off-screen.
       if (start.isFinite) {
@@ -1902,7 +1947,7 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
     }
     SelectionPoint? endPoint;
     if (endGeometry.endSelectionPoint != null) {
-      final Matrix4 endTransform =  getTransformFrom(selectables[endIndexWalker]);
+      final Matrix4 endTransform = getTransformFrom(selectables[endIndexWalker]);
       final Offset end = MatrixUtils.transformPoint(endTransform, endGeometry.endSelectionPoint!.localPosition);
       // It can be NaN if it is detached or off-screen.
       if (end.isFinite) {
@@ -1986,8 +2031,8 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
       final Rect? drawableArea = hasSize ? Rect
         .fromLTWH(0, 0, containerSize.width, containerSize.height)
         .inflate(_kSelectionHandleDrawableAreaPadding) : null;
-      final bool hideStartHandle = value.startSelectionPoint == null || drawableArea ==  null || !drawableArea.contains(value.startSelectionPoint!.localPosition);
+      final bool hideStartHandle = value.startSelectionPoint == null || drawableArea == null || !drawableArea.contains(value.startSelectionPoint!.localPosition);
-      final bool hideEndHandle = value.endSelectionPoint == null || drawableArea ==  null|| !drawableArea.contains(value.endSelectionPoint!.localPosition);
+      final bool hideEndHandle = value.endSelectionPoint == null || drawableArea == null|| !drawableArea.contains(value.endSelectionPoint!.localPosition);
       effectiveStartHandle = hideStartHandle ? null : _startHandleLayer;
       effectiveEndHandle = hideEndHandle ? null : _endHandleLayer;
     }
@@ -2047,6 +2092,34 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
     );
   }
 
+  // Clears the selection on all selectables not in the range of
+  // currentSelectionStartIndex..currentSelectionEndIndex.
+  //
+  // If one of the edges does not exist, then this method will clear the selection
+  // in all selectables except the existing edge.
+  //
+  // If neither of the edges exist this method immediately returns.
+  void _flushInactiveSelections() {
+    if (currentSelectionStartIndex == -1 && currentSelectionEndIndex == -1) {
+      return;
+    }
+    if (currentSelectionStartIndex == -1 || currentSelectionEndIndex == -1) {
+      final int skipIndex = currentSelectionStartIndex == -1 ? currentSelectionEndIndex : currentSelectionStartIndex;
+      selectables
+        .where((Selectable target) => target != selectables[skipIndex])
+        .forEach((Selectable target) => dispatchSelectionEventToChild(target, const ClearSelectionEvent()));
+      return;
+    }
+    final int skipStart = min(currentSelectionStartIndex, currentSelectionEndIndex);
+    final int skipEnd = max(currentSelectionStartIndex, currentSelectionEndIndex);
+    for (int index = 0; index < selectables.length; index += 1) {
+      if (index >= skipStart && index <= skipEnd) {
+        continue;
+      }
+      dispatchSelectionEventToChild(selectables[index], const ClearSelectionEvent());
+    }
+  }
+
   /// Selects all contents of all selectables.
   @protected
   SelectionResult handleSelectAll(SelectAllSelectionEvent event) {
@@ -2290,7 +2363,7 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
     bool hasFoundEdgeIndex = false;
     SelectionResult? result;
     for (int index = 0; index < selectables.length && !hasFoundEdgeIndex; index += 1) {
-      final Selectable child =  selectables[index];
+      final Selectable child = selectables[index];
       final SelectionResult childResult = dispatchSelectionEventToChild(child, event);
       switch (childResult) {
         case SelectionResult.next:
@@ -2323,6 +2396,7 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
     } else {
       currentSelectionStartIndex = newIndex;
     }
+    _flushInactiveSelections();
     // The result can only be null if the loop went through the entire list
     // without any of the selection returned end or previous. In this case, the
     // caller of this method needs to find the next selectable in their list.
@@ -2345,13 +2419,39 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
       return true;
     }());
     SelectionResult? finalResult;
-    int newIndex = isEnd ? currentSelectionEndIndex : currentSelectionStartIndex;
+    // Determines if the edge being adjusted is within the current viewport.
+    //  - If so, we begin the search for the new selection edge position at the
+    //    currentSelectionEndIndex/currentSelectionStartIndex.
+    //  - If not, we attempt to locate the new selection edge starting from
+    //    the opposite end.
+    //  - If neither edge is in the current viewport, the search for the new
+    //    selection edge position begins at 0.
+    //
+    // This can happen when there is a scrollable child and the edge being adjusted
+    // has been scrolled out of view.
+    final bool isCurrentEdgeWithinViewport = isEnd ? _selectionGeometry.endSelectionPoint != null : _selectionGeometry.startSelectionPoint != null;
+    final bool isOppositeEdgeWithinViewport = isEnd ? _selectionGeometry.startSelectionPoint != null : _selectionGeometry.endSelectionPoint != null;
+    int newIndex = switch ((isEnd, isCurrentEdgeWithinViewport, isOppositeEdgeWithinViewport)) {
+      (true, true, true) => currentSelectionEndIndex,
+      (true, true, false) => currentSelectionEndIndex,
+      (true, false, true) => currentSelectionStartIndex,
+      (true, false, false) => 0,
+      (false, true, true) => currentSelectionStartIndex,
+      (false, true, false) => currentSelectionStartIndex,
+      (false, false, true) => currentSelectionEndIndex,
+      (false, false, false) => 0,
+    };
     bool? forward;
     late SelectionResult currentSelectableResult;
-    // This loop sends the selection event to the
+    // This loop sends the selection event to one of the following to determine
-    // currentSelectionEndIndex/currentSelectionStartIndex to determine the
+    // the direction of the search.
-    // direction of the search. If the result is `SelectionResult.next`, this
+    //  - currentSelectionEndIndex/currentSelectionStartIndex if the current edge
-    // loop look backward. Otherwise, it looks forward.
+    //    is in the current viewport.
+    //  - The opposite edge index if the current edge is not in the current viewport.
+    //  - Index 0 if neither edge is in the current viewport.
+    //
+    // If the result is `SelectionResult.next`, this loop look backward.
+    // Otherwise, it looks forward.
     //
     // The terminate condition are:
     // 1. the selectable returns end, pending, none.
@@ -2391,6 +2491,7 @@ abstract class MultiSelectableSelectionContainerDelegate extends SelectionContai
     } else {
       currentSelectionStartIndex = newIndex;
     }
+    _flushInactiveSelections();
     return finalResult!;
   }
 }

packages/flutter/test/material/selection_area_test.dart

@@ -224,8 +224,14 @@ void main() {
 
     // Backwards selection.
     await gesture.down(textOffsetToPosition(paragraph, 3));
-    await tester.pumpAndSettle();
+    await tester.pump();
-    expect(content, isNull);
+    await gesture.up();
+    await tester.pumpAndSettle(kDoubleTapTimeout);
+    expect(content, isNotNull);
+    expect(content!.plainText, '');
+
+    await gesture.down(textOffsetToPosition(paragraph, 3));
+    await tester.pump();
     await gesture.moveTo(textOffsetToPosition(paragraph, 0));
     await gesture.up();
     await tester.pump();

packages/flutter/test/rendering/paragraph_test.dart

@@ -978,7 +978,8 @@ void main() {
           granularity: TextGranularity.word,
         ),
       );
-      expect(paragraph.selections.length, 0); // how []are you
+      expect(paragraph.selections.length, 1); // how []are you
+      expect(paragraph.selections[0], const TextSelection.collapsed(offset: 4));
 
       // Equivalent to sending shift + alt + arrow-left.
       registrar.selectables[0].dispatchSelectionEvent(

packages/flutter/test/widgets/selectable_region_test.dart

@@ -281,7 +281,7 @@ void main() {
       semantics.dispose();
     });
 
-    testWidgetsWithLeakTracking('mouse selection always cancels previous selection', (WidgetTester tester) async {
+    testWidgets('mouse single-click selection collapses the selection', (WidgetTester tester) async {
       final UniqueKey spy = UniqueKey();
       final FocusNode focusNode = FocusNode();
       addTearDown(focusNode.dispose);
@@ -300,9 +300,14 @@ void main() {
       final RenderSelectionSpy renderSelectionSpy = tester.renderObject<RenderSelectionSpy>(find.byKey(spy));
       final TestGesture gesture = await tester.startGesture(const Offset(200.0, 200.0), kind: PointerDeviceKind.mouse);
       addTearDown(gesture.removePointer);
+      await tester.pump();
+      await gesture.up();
       await tester.pumpAndSettle();
-      expect(renderSelectionSpy.events.length, 1);
+      expect(renderSelectionSpy.events.length, 2);
-      expect(renderSelectionSpy.events[0], isA<ClearSelectionEvent>());
+      expect(renderSelectionSpy.events[0], isA<SelectionEdgeUpdateEvent>());
+      expect((renderSelectionSpy.events[0] as SelectionEdgeUpdateEvent).type, SelectionEventType.startEdgeUpdate);
+      expect(renderSelectionSpy.events[1], isA<SelectionEdgeUpdateEvent>());
+      expect((renderSelectionSpy.events[1] as SelectionEdgeUpdateEvent).type, SelectionEventType.endEdgeUpdate);
     }, skip: kIsWeb); // https://github.com/flutter/flutter/issues/102410.
 
     testWidgetsWithLeakTracking('touch long press sends select-word event', (WidgetTester tester) async {
@@ -474,7 +479,7 @@ void main() {
       await tester.pump(const Duration(milliseconds: 500));
       await gesture.up();
       expect(
-        renderSelectionSpy.events.every((SelectionEvent element) => element is ClearSelectionEvent),
+        renderSelectionSpy.events.every((SelectionEvent element) => element is SelectionEdgeUpdateEvent),
         isTrue,
       );
     });
@@ -543,7 +548,7 @@ void main() {
   }, variant: TargetPlatformVariant.all());
 
   group('SelectionArea integration', () {
-    testWidgetsWithLeakTracking('mouse can select single text', (WidgetTester tester) async {
+    testWidgets('mouse can select single text on desktop platforms', (WidgetTester tester) async {
       final FocusNode focusNode = FocusNode();
       addTearDown(focusNode.dispose);
 
@@ -574,13 +579,17 @@ void main() {
       // Check backward selection.
       await gesture.moveTo(textOffsetToPosition(paragraph, 1));
       await tester.pump();
+      expect(paragraph.selections.isEmpty, isFalse);
       expect(paragraph.selections[0], const TextSelection(baseOffset: 2, extentOffset: 1));
 
       // Start a new drag.
       await gesture.up();
+      await tester.pumpAndSettle();
+
       await gesture.down(textOffsetToPosition(paragraph, 5));
       await tester.pumpAndSettle();
-      expect(paragraph.selections.isEmpty, isTrue);
+      expect(paragraph.selections.isEmpty, isFalse);
+      expect(paragraph.selections[0], const TextSelection.collapsed(offset: 5));
 
       // Selecting across line should select to the end.
       await gesture.moveTo(textOffsetToPosition(paragraph, 5) + const Offset(0.0, 200.0));
@@ -588,7 +597,60 @@ void main() {
       expect(paragraph.selections[0], const TextSelection(baseOffset: 5, extentOffset: 11));
 
       await gesture.up();
-    });
+    }, variant: TargetPlatformVariant.desktop());
+
+    testWidgetsWithLeakTracking('mouse can select single text on mobile platforms', (WidgetTester tester) async {
+      final FocusNode focusNode = FocusNode();
+      addTearDown(focusNode.dispose);
+
+      await tester.pumpWidget(
+        MaterialApp(
+          home: SelectableRegion(
+            focusNode: focusNode,
+            selectionControls: materialTextSelectionControls,
+            child: const Center(
+              child: Text('How are you'),
+            ),
+          ),
+        ),
+      );
+      final RenderParagraph paragraph = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you'), matching: find.byType(RichText)));
+      final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph, 2), kind: PointerDeviceKind.mouse);
+      addTearDown(gesture.removePointer);
+      await tester.pump();
+
+      await gesture.moveTo(textOffsetToPosition(paragraph, 4));
+      await tester.pump();
+      expect(paragraph.selections[0], const TextSelection(baseOffset: 2, extentOffset: 4));
+
+      await gesture.moveTo(textOffsetToPosition(paragraph, 6));
+      await tester.pump();
+      expect(paragraph.selections[0], const TextSelection(baseOffset: 2, extentOffset: 6));
+
+      // Check backward selection.
+      await gesture.moveTo(textOffsetToPosition(paragraph, 1));
+      await tester.pump();
+      expect(paragraph.selections.isEmpty, isFalse);
+      expect(paragraph.selections[0], const TextSelection(baseOffset: 2, extentOffset: 1));
+
+      // Start a new drag.
+      await gesture.up();
+      await tester.pumpAndSettle();
+
+      await gesture.down(textOffsetToPosition(paragraph, 5));
+      await tester.pumpAndSettle();
+      await gesture.moveTo(textOffsetToPosition(paragraph, 6));
+      await tester.pump();
+      expect(paragraph.selections.isEmpty, isFalse);
+      expect(paragraph.selections[0], const TextSelection(baseOffset: 5, extentOffset: 6));
+
+      // Selecting across line should select to the end.
+      await gesture.moveTo(textOffsetToPosition(paragraph, 5) + const Offset(0.0, 200.0));
+      await tester.pump();
+      expect(paragraph.selections[0], const TextSelection(baseOffset: 5, extentOffset: 11));
+
+      await gesture.up();
+    }, variant: TargetPlatformVariant.mobile());
 
     testWidgetsWithLeakTracking('mouse can select word-by-word on double click drag', (WidgetTester tester) async {
       final FocusNode focusNode = FocusNode();
@@ -643,7 +705,8 @@ void main() {
       await gesture.down(textOffsetToPosition(paragraph, 5));
       await tester.pump();
       await gesture.up();
-      expect(paragraph.selections.isEmpty, isTrue);
+      expect(paragraph.selections.isEmpty, isFalse);
+      expect(paragraph.selections[0], const TextSelection.collapsed(offset: 5));
       await tester.pump(kDoubleTapTimeout);
 
       // Double-click.
@@ -761,13 +824,13 @@ void main() {
       // Should clear the selection on paragraph 3.
       expect(paragraph1.selections[0], const TextSelection(baseOffset: 0, extentOffset: 12));
       expect(paragraph2.selections[0], const TextSelection(baseOffset: 0, extentOffset: 6));
-      expect(paragraph3.selections.isEmpty, true);
+      expect(paragraph3.selections.isEmpty, isTrue);
 
       await gesture.moveTo(textOffsetToPosition(paragraph1, 4));
       // Should clear the selection on paragraph 2.
       expect(paragraph1.selections[0], const TextSelection(baseOffset: 0, extentOffset: 7));
-      expect(paragraph2.selections.isEmpty, true);
+      expect(paragraph2.selections.isEmpty, isTrue);
-      expect(paragraph3.selections.isEmpty, true);
+      expect(paragraph3.selections.isEmpty, isTrue);
 
       await gesture.up();
     }, skip: kIsWeb); // https://github.com/flutter/flutter/issues/125582.
@@ -863,6 +926,52 @@ void main() {
       await gesture.up();
     });
 
+    testWidgetsWithLeakTracking('collapsing selection should clear selection of all other selectables', (WidgetTester tester) async {
+      final FocusNode focusNode = FocusNode();
+      addTearDown(focusNode.dispose);
+
+      await tester.pumpWidget(
+        MaterialApp(
+          home: SelectableRegion(
+            focusNode: focusNode,
+            selectionControls: materialTextSelectionControls,
+            child: const Column(
+              children: <Widget>[
+                Text('How are you?'),
+                Text('Good, and you?'),
+                Text('Fine, thank you.'),
+              ],
+            ),
+          ),
+        ),
+      );
+      final RenderParagraph paragraph1 = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you?'), matching: find.byType(RichText)));
+      final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph1, 2), kind: PointerDeviceKind.mouse);
+      addTearDown(gesture.removePointer);
+      await tester.pump();
+      await gesture.up();
+      await tester.pumpAndSettle();
+      expect(paragraph1.selections[0], const TextSelection.collapsed(offset: 2));
+
+      final RenderParagraph paragraph2 = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('Good, and you?'), matching: find.byType(RichText)));
+      await gesture.down(textOffsetToPosition(paragraph2, 5));
+      await tester.pump();
+      await gesture.up();
+      await tester.pumpAndSettle();
+      expect(paragraph1.selections.isEmpty, isTrue);
+      expect(paragraph2.selections[0], const TextSelection.collapsed(offset: 5));
+
+      final RenderParagraph paragraph3 = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('Fine, thank you.'), matching: find.byType(RichText)));
+      await gesture.down(textOffsetToPosition(paragraph3, 13));
+      await tester.pump();
+      await gesture.up();
+      await tester.pumpAndSettle();
+
+      expect(paragraph1.selections.isEmpty, isTrue);
+      expect(paragraph2.selections.isEmpty, isTrue);
+      expect(paragraph3.selections[0], const TextSelection.collapsed(offset: 13));
+    });
+
     testWidgetsWithLeakTracking('mouse can work with disabled container', (WidgetTester tester) async {
       final FocusNode focusNode = FocusNode();
       addTearDown(focusNode.dispose);
@@ -1108,10 +1217,11 @@ void main() {
         expect(buttonTypes, contains(ContextMenuButtonType.selectAll));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
-        // Clear selection.
+        // Collapse selection.
         await tester.tapAt(textOffsetToPosition(paragraph, 9));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        expect(paragraph.selections.isEmpty, isFalse);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 9));
         expect(find.byKey(toolbarKey), findsNothing);
       },
       variant: TargetPlatformVariant.only(TargetPlatform.iOS),
@@ -1151,7 +1261,9 @@ void main() {
         expect(find.byKey(toolbarKey), findsNothing);
 
         final RenderParagraph paragraph = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you'), matching: find.byType(RichText)));
+        final TestGesture primaryMouseButtonGesture = await tester.createGesture(kind: PointerDeviceKind.mouse);
         final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph, 2), kind: PointerDeviceKind.mouse, buttons: kSecondaryMouseButton);
+        addTearDown(primaryMouseButtonGesture.removePointer);
         addTearDown(gesture.removePointer);
         await tester.pump();
         expect(paragraph.selections[0], const TextSelection(baseOffset: 0, extentOffset: 3));
@@ -1185,10 +1297,14 @@ void main() {
         expect(buttonTypes, contains(ContextMenuButtonType.selectAll));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
-        // Clear selection.
+        // Collapse selection.
-        await tester.tapAt(textOffsetToPosition(paragraph, 1));
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 1));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        await primaryMouseButtonGesture.up();
+        await tester.pumpAndSettle();
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 1));
         expect(find.byKey(toolbarKey), findsNothing);
       },
       variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }),
@@ -1229,6 +1345,8 @@ void main() {
 
         final RenderParagraph paragraph = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you'), matching: find.byType(RichText)));
         final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph, 2), kind: PointerDeviceKind.mouse, buttons: kSecondaryMouseButton);
+        final TestGesture primaryMouseButtonGesture = await tester.createGesture(kind: PointerDeviceKind.mouse);
+        addTearDown(primaryMouseButtonGesture.removePointer);
         addTearDown(gesture.removePointer);
         await tester.pump();
         expect(paragraph.selections[0], const TextSelection(baseOffset: 0, extentOffset: 3));
@@ -1286,10 +1404,14 @@ void main() {
         expect(buttonTypes, contains(ContextMenuButtonType.selectAll));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
-        // Clear selection.
+        // Collapse selection.
-        await tester.tapAt(textOffsetToPosition(paragraph, 1));
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 1));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        await primaryMouseButtonGesture.up();
+        await tester.pumpAndSettle();
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 1));
         expect(find.byKey(toolbarKey), findsNothing);
       },
       variant: TargetPlatformVariant.only(TargetPlatform.macOS),
@@ -1330,21 +1452,24 @@ void main() {
 
         final RenderParagraph paragraph = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you'), matching: find.byType(RichText)));
         final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph, 2), kind: PointerDeviceKind.mouse, buttons: kSecondaryMouseButton);
+        final TestGesture primaryMouseButtonGesture = await tester.createGesture(kind: PointerDeviceKind.mouse);
+        addTearDown(primaryMouseButtonGesture.removePointer);
         addTearDown(gesture.removePointer);
         await tester.pump();
-        // Selection is collapsed so none is reported.
-        expect(paragraph.selections.isEmpty, true);
-
         await gesture.up();
         await tester.pump();
 
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 2));
         expect(buttonTypes.length, 1);
         expect(buttonTypes, contains(ContextMenuButtonType.selectAll));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
         await gesture.down(textOffsetToPosition(paragraph, 6));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 6));
 
         await gesture.up();
         await tester.pump();
@@ -1355,7 +1480,8 @@ void main() {
 
         await gesture.down(textOffsetToPosition(paragraph, 9));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 9));
 
         await gesture.up();
         await tester.pump();
@@ -1364,20 +1490,23 @@ void main() {
         expect(buttonTypes, contains(ContextMenuButtonType.selectAll));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
-        // Clear selection.
+        // Collapse selection.
-        await tester.tapAt(textOffsetToPosition(paragraph, 1));
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 1));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        await primaryMouseButtonGesture.up();
+        await tester.pumpAndSettle(kDoubleTapTimeout);
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 1));
         expect(find.byKey(toolbarKey), findsNothing);
 
         // Create an uncollapsed selection by dragging.
-        final TestGesture dragGesture = await tester.startGesture(textOffsetToPosition(paragraph, 0), kind: PointerDeviceKind.mouse);
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 0));
-        addTearDown(dragGesture.removePointer);
         await tester.pump();
-        await dragGesture.moveTo(textOffsetToPosition(paragraph, 5));
+        await primaryMouseButtonGesture.moveTo(textOffsetToPosition(paragraph, 5));
         await tester.pump();
         expect(paragraph.selections[0], const TextSelection(baseOffset: 0, extentOffset: 5));
-        await dragGesture.up();
+        await primaryMouseButtonGesture.up();
         await tester.pump();
 
         // Right click on previous selection should not collapse the selection.
@@ -1394,13 +1523,18 @@ void main() {
         await tester.pump();
         await gesture.up();
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 7));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
-        // Clear selection.
+        // Collapse selection.
-        await tester.tapAt(textOffsetToPosition(paragraph, 1));
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 1));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        await primaryMouseButtonGesture.up();
+        await tester.pumpAndSettle();
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 1));
         expect(find.byKey(toolbarKey), findsNothing);
       },
       variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.android, TargetPlatform.fuchsia, TargetPlatform.windows }),
@@ -1441,13 +1575,15 @@ void main() {
 
         final RenderParagraph paragraph = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you'), matching: find.byType(RichText)));
         final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph, 2), kind: PointerDeviceKind.mouse, buttons: kSecondaryMouseButton);
+        final TestGesture primaryMouseButtonGesture = await tester.createGesture(kind: PointerDeviceKind.mouse);
+        addTearDown(primaryMouseButtonGesture.removePointer);
         addTearDown(gesture.removePointer);
         await tester.pump();
-        // Selection is collapsed so none is reported.
-        expect(paragraph.selections.isEmpty, true);
-
         await gesture.up();
         await tester.pump();
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 2));
 
         // Context menu toggled on.
         expect(buttonTypes.length, 1);
@@ -1456,17 +1592,18 @@ void main() {
 
         await gesture.down(textOffsetToPosition(paragraph, 6));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
-
         await gesture.up();
         await tester.pump();
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 2));
 
-        // Context menu toggled off.
+        // Context menu toggled off. Selection remains the same.
         expect(find.byKey(toolbarKey), findsNothing);
 
         await gesture.down(textOffsetToPosition(paragraph, 9));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 9));
 
         await gesture.up();
         await tester.pump();
@@ -1476,19 +1613,22 @@ void main() {
         expect(buttonTypes, contains(ContextMenuButtonType.selectAll));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
-        // Clear selection.
+        // Collapse selection.
-        await tester.tapAt(textOffsetToPosition(paragraph, 1));
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 1));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        await primaryMouseButtonGesture.up();
+        await tester.pumpAndSettle(kDoubleTapTimeout);
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 1));
         expect(find.byKey(toolbarKey), findsNothing);
 
-        final TestGesture dragGesture = await tester.startGesture(textOffsetToPosition(paragraph, 0), kind: PointerDeviceKind.mouse);
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 0));
-        addTearDown(dragGesture.removePointer);
         await tester.pump();
-        await dragGesture.moveTo(textOffsetToPosition(paragraph, 5));
+        await primaryMouseButtonGesture.moveTo(textOffsetToPosition(paragraph, 5));
         await tester.pump();
         expect(paragraph.selections[0], const TextSelection(baseOffset: 0, extentOffset: 5));
-        await dragGesture.up();
+        await primaryMouseButtonGesture.up();
         await tester.pump();
 
         // Right click on previous selection should not collapse the selection.
@@ -1514,13 +1654,18 @@ void main() {
         await tester.pump();
         await gesture.up();
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 7));
         expect(find.byKey(toolbarKey), findsOneWidget);
 
-        // Clear selection.
+        // Collapse selection.
-        await tester.tapAt(textOffsetToPosition(paragraph, 1));
+        await primaryMouseButtonGesture.down(textOffsetToPosition(paragraph, 1));
         await tester.pump();
-        expect(paragraph.selections.isEmpty, true);
+        await primaryMouseButtonGesture.up();
+        await tester.pumpAndSettle();
+        // Selection is collapsed.
+        expect(paragraph.selections.isEmpty, false);
+        expect(paragraph.selections[0], const TextSelection.collapsed(offset: 1));
         expect(find.byKey(toolbarKey), findsNothing);
       },
       variant: TargetPlatformVariant.only(TargetPlatform.linux),
@@ -2414,7 +2559,9 @@ void main() {
       expect(paragraph1.selections.length, 1);
       expect(paragraph1.selections[0].start, 2);
       expect(paragraph1.selections[0].end, 12);
-      expect(paragraph2.selections.length, 0);
+      expect(paragraph2.selections.length, 1);
+      expect(paragraph2.selections[0].start, 0);
+      expect(paragraph2.selections[0].end, 0);
 
       await sendKeyCombination(tester, SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true, alt: alt, control: control));
       await tester.pump();
@@ -2424,7 +2571,9 @@ void main() {
       expect(paragraph1.selections.length, 1);
       expect(paragraph1.selections[0].start, 2);
       expect(paragraph1.selections[0].end, 8);
-      expect(paragraph2.selections.length, 0);
+      expect(paragraph2.selections.length, 1);
+      expect(paragraph2.selections[0].start, 0);
+      expect(paragraph2.selections[0].end, 0);
     }, variant: TargetPlatformVariant.all());
 
     testWidgetsWithLeakTracking('can use keyboard to granularly extend selection - line', (WidgetTester tester) async {
@@ -2507,7 +2656,9 @@ void main() {
       expect(paragraph1.selections.length, 1);
       expect(paragraph1.selections[0].start, 2);
       expect(paragraph1.selections[0].end, 12);
-      expect(paragraph2.selections.length, 0);
+      expect(paragraph2.selections.length, 1);
+      expect(paragraph2.selections[0].start, 0);
+      expect(paragraph2.selections[0].end, 0);
 
       await sendKeyCombination(tester, SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true, alt: alt, meta: meta));
       await tester.pump();
@@ -2594,8 +2745,12 @@ void main() {
       expect(paragraph1.selections.length, 1);
       expect(paragraph1.selections[0].start, 0);
       expect(paragraph1.selections[0].end, 2);
-      expect(paragraph2.selections.length, 0);
+      expect(paragraph2.selections.length, 1);
-      expect(paragraph3.selections.length, 0);
+      expect(paragraph2.selections[0].start, 0);
+      expect(paragraph2.selections[0].end, 0);
+      expect(paragraph3.selections.length, 1);
+      expect(paragraph3.selections[0].start, 0);
+      expect(paragraph3.selections[0].end, 0);
     }, variant: TargetPlatformVariant.all());
 
     testWidgetsWithLeakTracking('can use keyboard to directionally extend selection', (WidgetTester tester) async {
@@ -2666,7 +2821,9 @@ void main() {
       expect(paragraph2.selections.length, 1);
       expect(paragraph2.selections[0].start, 2);
       expect(paragraph2.selections[0].end, 6);
-      expect(paragraph3.selections.length, 0);
+      expect(paragraph3.selections.length, 1);
+      expect(paragraph3.selections[0].start, 0);
+      expect(paragraph3.selections[0].end, 0);
 
       await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowUp, shift: true));
       await tester.pump();
@@ -3017,8 +3174,14 @@ void main() {
 
     // Backwards selection.
     await mouseGesture.down(textOffsetToPosition(paragraph, 3));
-    await tester.pumpAndSettle();
+    await tester.pump();
-    expect(content, isNull);
+    await mouseGesture.up();
+    await tester.pumpAndSettle(kDoubleTapTimeout);
+    expect(content, isNotNull);
+    expect(content!.plainText, '');
+
+    await mouseGesture.down(textOffsetToPosition(paragraph, 3));
+    await tester.pump();
 
     await mouseGesture.moveTo(textOffsetToPosition(paragraph, 0));
     await tester.pumpAndSettle();
@@ -3045,9 +3208,10 @@ void main() {
     // Called on tap.
     await mouseGesture.down(textOffsetToPosition(paragraph, 0));
     await tester.pumpAndSettle();
-    expect(content, isNull);
     await mouseGesture.up();
-    await tester.pumpAndSettle();
+    await tester.pumpAndSettle(kDoubleTapTimeout);
+    expect(content, isNotNull);
+    expect(content!.plainText, '');
 
     // With touch gestures.
 
@@ -3224,7 +3388,7 @@ void main() {
     expect(paragraph2.selections.length, 1);
     expect(paragraph2.selections[0].start, 0);
     expect(paragraph2.selections[0].end, 8);
-    expect(paragraph3.selections.length, 0);
+    expect(paragraph3.selections.length, 1);
     expect(content, isNotNull);
     expect(content!.plainText, 'w are you?Good, an');
 
@@ -3233,8 +3397,8 @@ void main() {
     expect(paragraph1.selections.length, 1);
     expect(paragraph1.selections[0].start, 2);
     expect(paragraph1.selections[0].end, 7);
-    expect(paragraph2.selections.length, 0);
+    expect(paragraph2.selections.length, 1);
-    expect(paragraph3.selections.length, 0);
+    expect(paragraph3.selections.length, 1);
     expect(content, isNotNull);
     expect(content!.plainText, 'w are');
 
@@ -3243,8 +3407,8 @@ void main() {
     expect(paragraph1.selections.length, 1);
     expect(paragraph1.selections[0].start, 0);
     expect(paragraph1.selections[0].end, 2);
-    expect(paragraph2.selections.length, 0);
+    expect(paragraph2.selections.length, 1);
-    expect(paragraph3.selections.length, 0);
+    expect(paragraph3.selections.length, 1);
     expect(content, isNotNull);
     expect(content!.plainText, 'Ho');
   });