DataGrid: Fix the column headers scroll position reset in RTL mode with native scrolling

e2e/testcafe-devextreme/tests/dataGrid/common/scrolling.ts

@@ -508,6 +508,80 @@ test('Horizontal scrolling should work correctly in RTL mode with native scrolli
   await removeStylesheetRulesFromPage();
 });
 
+test('Column headers should keep the scroll position after resizing a column in RTL mode with native scrolling', async (t) => {
+  const dataGrid = new DataGrid('#container');
+  const rowsScrollContainer = dataGrid.getScrollContainer();
+  const headersScrollContainer = dataGrid.getHeadersScrollContainer();
+
+  await t
+    .expect(dataGrid.isReady())
+    .ok();
+
+  const initialScrollLeft = await dataGrid.getScrollLeft();
+
+  await dataGrid.scrollTo(t, { x: initialScrollLeft - 100 });
+
+  await t
+    .expect(rowsScrollContainer.scrollLeft)
+    .eql(-100)
+    .expect(headersScrollContainer.scrollLeft)
+    .eql(-100);
+
+  await dataGrid.resizeHeader(2, -30);
+
+  await t
+    .expect(rowsScrollContainer.scrollLeft)
+    .eql(-100)
+    .expect(headersScrollContainer.scrollLeft)
+    .eql(-100);
+}).before(async () => createWidget('dxDataGrid', {
+  rtlEnabled: true,
+  width: 500,
+  dataSource: getData(5, 10),
+  columnAutoWidth: true,
+  allowColumnResizing: true,
+  columnResizingMode: 'nextColumn',
+  scrolling: {
+    useNative: true,
+  },
+}));
+
+test('Column headers should keep the scroll position after repaint in RTL mode with native scrolling', async (t) => {
+  const dataGrid = new DataGrid('#container');
+  const rowsScrollContainer = dataGrid.getScrollContainer();
+  const headersScrollContainer = dataGrid.getHeadersScrollContainer();
+
+  await t
+    .expect(dataGrid.isReady())
+    .ok();
+
+  const initialScrollLeft = await dataGrid.getScrollLeft();
+
+  await dataGrid.scrollTo(t, { x: initialScrollLeft - 100 });
+
+  await t
+    .expect(rowsScrollContainer.scrollLeft)
+    .eql(-100)
+    .expect(headersScrollContainer.scrollLeft)
+    .eql(-100);
+
+  await dataGrid.repaint();
+
+  await t
+    .expect(rowsScrollContainer.scrollLeft)
+    .eql(-100)
+    .expect(headersScrollContainer.scrollLeft)
+    .eql(-100);
+}).before(async () => createWidget('dxDataGrid', {
+  rtlEnabled: true,
+  width: 500,
+  dataSource: getData(5, 10),
+  columnAutoWidth: true,
+  scrolling: {
+    useNative: true,
+  },
+}));
+
 test('Column headers should have the correct scroll position after refreshing the data twice when RTL and virtual scrolling are enabled (T1333941)', async (t) => {
   const dataGrid = new DataGrid('#container');
 

packages/devextreme/js/__internal/grids/grid_core/views/__tests__/columns_view.scroll_position.integration.test.ts

@@ -0,0 +1,73 @@
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  it,
+  jest,
+} from '@jest/globals';
+
+import {
+  afterTest,
+  beforeTest,
+  createDataGrid,
+} from '../../__tests__/__mock__/helpers/utils';
+
+const createGrid = (rtlEnabled: boolean): ReturnType<typeof createDataGrid> => createDataGrid({
+  rtlEnabled,
+  dataSource: [{ id: 1, a: 'a', b: 'b' }],
+  columns: ['a', 'b'],
+  scrolling: {
+    useNative: true,
+  },
+});
+
+describe('ColumnHeadersView horizontal scroll position', () => {
+  beforeEach(beforeTest);
+  afterEach(afterTest);
+
+  describe('when the headers are scrolled to a negative position in RTL', () => {
+    it('should restore the position after the headers are rendered again', async () => {
+      const { instance } = await createGrid(true);
+      const columnHeadersView = instance.getView('columnHeadersView');
+
+      columnHeadersView.scrollTo({ left: -100 });
+
+      const scrollToSpy = jest.spyOn(columnHeadersView, 'scrollTo');
+
+      columnHeadersView.render();
+      jest.runAllTimers();
+
+      expect(scrollToSpy).toHaveBeenCalledWith({ left: -100 });
+    });
+
+    it('should restore the position after the headers are resized', async () => {
+      const { instance } = await createGrid(true);
+      const columnHeadersView = instance.getView('columnHeadersView');
+
+      columnHeadersView.scrollTo({ left: -100 });
+
+      const scrollToSpy = jest.spyOn(columnHeadersView, 'scrollTo');
+
+      columnHeadersView.resize();
+
+      expect(scrollToSpy).toHaveBeenCalledWith({ left: -100 });
+    });
+  });
+
+  describe('when the headers are scrolled to a positive position in LTR', () => {
+    it('should restore the position after the headers are rendered again', async () => {
+      const { instance } = await createGrid(false);
+      const columnHeadersView = instance.getView('columnHeadersView');
+
+      columnHeadersView.scrollTo({ left: 100 });
+
+      const scrollToSpy = jest.spyOn(columnHeadersView, 'scrollTo');
+
+      columnHeadersView.render();
+      jest.runAllTimers();
+
+      expect(scrollToSpy).toHaveBeenCalledWith({ left: 100 });
+    });
+  });
+});

packages/devextreme/js/__internal/grids/grid_core/views/m_columns_view.ts

@@ -204,7 +204,7 @@ export class ColumnsView extends ColumnStateMixin(modules.View) {
   protected _columnChooserView!: ColumnChooserView;
 
   public init() {
-    this._scrollLeft = -1;
+    this._scrollLeft = undefined;
     this._columnsController = this.getController('columns');
     this._dataController = this.getController('data');
     this.adaptiveColumnsController = this.getController('adaptiveColumns');
@@ -1078,7 +1078,7 @@ export class ColumnsView extends ColumnStateMixin(modules.View) {
   protected updateScrollLeftPosition(): void {
     const scrollLeft = this._scrollLeft;
 
-    if (scrollLeft >= 0) {
+    if (isDefined(scrollLeft)) {
       this._scrollLeft = 0;
       this.scrollTo({ left: scrollLeft });
     }