From 9771eca5d7e4a032bf71164bd1aab34e4aad5bd9 Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Wed, 15 Jul 2026 22:18:00 +0300
Subject: [PATCH 01/11] Refactor _synchronizeColumns method

---
 .../js/__internal/grids/grid_core/m_utils.ts  |  20 ++-
 .../grids/grid_core/views/m_grid_view.ts      | 161 +++++++++---------
 .../js/__internal/ui/popover/popover.ts       |   2 +-
 3 files changed, 96 insertions(+), 87 deletions(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
index f03a205a92c4..af9ca4fd1b3b 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
@@ -70,6 +70,12 @@ export function isDateType(dataType: string | undefined): boolean {
   return dataType === 'date' || dataType === 'datetime';
 }
 
+export interface SelectionRange {
+  selectionStart: number;
+  selectionEnd: number;
+  selectionDirection?: 'forward' | 'backward' | 'none';
+}
+
 const getIntervalSelector = function () {
   const data = arguments[1];
   const value = this.calculateCellValue(data);
@@ -562,23 +568,27 @@ export default {
 
   isDateType,
 
-  getSelectionRange(focusedElement) {
+  getSelectionRange(focusedElement): SelectionRange {
     try {
       if (focusedElement) {
         return {
           selectionStart: focusedElement.selectionStart,
           selectionEnd: focusedElement.selectionEnd,
+          selectionDirection: focusedElement.selectionDirection ?? undefined,
         };
       }
     } catch (e) { /* empty */ }
 
-    return {};
+    return {
+      selectionStart: -1,
+      selectionEnd: -1,
+    };
   },
 
-  setSelectionRange(focusedElement, selectionRange) {
+  setSelectionRange(focusedElement, selectionRange: SelectionRange): void {
     try {
-      if (focusedElement && focusedElement.setSelectionRange) {
-        focusedElement.setSelectionRange(selectionRange.selectionStart, selectionRange.selectionEnd);
+      if (focusedElement && focusedElement.setSelectionRange && selectionRange.selectionStart >= 0 && selectionRange.selectionEnd >= 0) {
+        focusedElement.setSelectionRange(selectionRange.selectionStart, selectionRange.selectionEnd, selectionRange.selectionDirection);
       }
     } catch (e) { /* empty */ }
   },
diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index b121904058a5..09460b162b88 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -23,7 +23,7 @@ import type { ColumnHeadersView } from '../column_headers/m_column_headers';
 import type { ColumnsController } from '../columns_controller/m_columns_controller';
 import type { DataController } from '../data_controller/m_data_controller';
 import modules from '../m_modules';
-import gridCoreUtils from '../m_utils';
+import gridCoreUtils, { type SelectionRange } from '../m_utils';
 import type { RowsView } from './m_rows_view';
 
 const BORDERS_CLASS = 'borders';
@@ -78,11 +78,17 @@ const calculateFreeWidthWithCurrentMinWidth = function (that, columnIndex, curre
   return calculateFreeWidth(that, widths.map((width, index) => (index === columnIndex ? currentMinWidth : width)));
 };
 
-const restoreFocus = function (focusedElement, selectionRange) {
+const restoreFocus = (focusedElement: Element, selectionRange: SelectionRange): void => {
   accessibility.hiddenFocus(focusedElement, true);
   gridCoreUtils.setSelectionRange(focusedElement, selectionRange);
 };
 
+interface MaxWidthController {
+  isModified: boolean;
+  set: (value: number) => void;
+  clear: () => void;
+}
+
 export class ResizingController extends modules.ViewController {
   private _refreshSizesHandler: any;
 
@@ -100,8 +106,6 @@ export class ResizingController extends modules.ViewController {
 
   private _prevContentMinHeight: any;
 
-  private _maxWidth: any;
-
   private _hasWidth: any;
 
   private _hasHeight: any;
@@ -122,6 +126,26 @@ export class ResizingController extends modules.ViewController {
 
   public resizeCompleted!: Callback;
 
+  private readonly _maxWidth: MaxWidthController = {
+    isModified: false,
+    set: (value): void => {
+      const $element = this.component.$element();
+
+      this._maxWidth.isModified = true;
+      $element.css('maxWidth', value);
+    },
+    clear: (): void => {
+      const $element = this.component.$element();
+
+      if (!this._maxWidth.isModified || !$element || !$element.get(0)) {
+        return;
+      }
+
+      this._maxWidth.isModified = false;
+      $element[0].style.maxWidth = '';
+    },
+  };
+
   protected callbackNames() {
     return ['resizeCompleted'];
   }
@@ -338,85 +362,55 @@ export class ResizingController extends modules.ViewController {
     }
   }
 
-  private _synchronizeColumns() {
-    const columnsController = this._columnsController;
-    const visibleColumns = columnsController.getVisibleColumns();
-    const columnAutoWidth = this.option('columnAutoWidth');
-    const hasUndefinedColumnWidth = visibleColumns.some((column) => !isDefined(column.width));
-    let needBestFit = this._needBestFit();
-    let hasMinWidth = false;
-    let resetBestFitMode;
-    let isColumnWidthsCorrected = false;
-    let resultWidths: any[] = [];
-    let focusedElement;
-    let selectionRange;
+  private _enableTemporaryBestFitMode(): () => void {
+    const $element = this.component.$element();
+    const focusedElement = domAdapter.getActiveElement($element.get(0) as HTMLElement | null);
+    const selectionRange = gridCoreUtils.getSelectionRange(focusedElement);
 
-    const normalizeWidthsByExpandColumns = function () {
-      let expandColumnWidth;
+    this._toggleBestFitMode(true);
 
-      each(visibleColumns, (index, column) => {
-        if (column.type === 'groupExpand') {
-          expandColumnWidth = resultWidths[index];
-        }
-      });
+    return (): void => {
+      this._toggleBestFitMode(false);
 
-      each(visibleColumns, (index, column) => {
-        if (column.type === 'groupExpand' && expandColumnWidth) {
-          resultWidths[index] = expandColumnWidth;
-        }
-      });
-    };
+      if (focusedElement && focusedElement !== domAdapter.getActiveElement()) {
+        const isFocusOutsideWindow = getBoundingRect(focusedElement).bottom < 0;
 
-    !needBestFit && each(visibleColumns, (index, column) => {
-      if (column.width === 'auto') {
-        needBestFit = true;
-        return false;
+        if (!isFocusOutsideWindow) {
+          restoreFocus(focusedElement, selectionRange);
+        }
       }
-      return undefined;
-    });
+    };
+  }
 
-    each(visibleColumns, (index, column) => {
-      if (column.minWidth) {
-        hasMinWidth = true;
-        return false;
-      }
-      return undefined;
-    });
+  private _synchronizeColumns():void {
+    const columnsController = this._columnsController;
+    const visibleColumns = columnsController.getVisibleColumns();
+    const columnAutoWidth = this.option('columnAutoWidth') as boolean;
+    const hasUndefinedColumnWidth = visibleColumns.some((column) => !isDefined(column.width));
+    const needBestFit = this._needBestFit() || visibleColumns.some((column) => column.width === 'auto');
+    const hasMinWidth = visibleColumns.some((column) => !!column.minWidth);
 
+    // Prepare for measurement
     this._toggleContentMinHeight(this._hasHeight); // T1047239, T1270354
-
     this._setVisibleWidths(visibleColumns, []);
-
-    const $element = this.component.$element();
-
-    if (needBestFit) {
-      // @ts-expect-error
-      focusedElement = domAdapter.getActiveElement($element.get(0));
-      selectionRange = gridCoreUtils.getSelectionRange(focusedElement);
-      this._toggleBestFitMode(true);
-      resetBestFitMode = true;
-    }
-
-    if ($element && $element.get(0) && this._maxWidth) {
-      delete this._maxWidth;
-      $element[0].style.maxWidth = '';
-    }
+    const restoreAfterBestFitMode = needBestFit && this._enableTemporaryBestFitMode();
+    this._maxWidth.clear();
 
     // eslint-disable-next-line @typescript-eslint/no-floating-promises
     deferUpdate(() => {
-      if (needBestFit) {
+      let resultWidths: (number | string | undefined)[] = [];
+
+      if (needBestFit || hasMinWidth) {
         resultWidths = this._getBestFitWidths();
+      }
 
-        each(visibleColumns, (index, column) => {
+      each(visibleColumns, (index, column) => {
+        if (needBestFit) {
           const columnId = columnsController.getColumnId(column);
           columnsController.columnOption(columnId, 'bestFitWidth', resultWidths[index], true);
-        });
-      } else if (hasMinWidth) {
-        resultWidths = this._getBestFitWidths();
-      }
+        }
 
-      each(visibleColumns, function (index) {
-        const { width } = this;
+        const { width } = column;
         if (width !== 'auto') {
           if (isDefined(width)) {
             resultWidths[index] = isNumeric(width) || isPixelWidth(width) ? parseFloat(width) : width;
@@ -426,21 +420,14 @@ export class ResizingController extends modules.ViewController {
         }
       });
 
-      if (resetBestFitMode) {
-        this._toggleBestFitMode(false);
-        resetBestFitMode = false;
-        if (focusedElement && focusedElement !== domAdapter.getActiveElement()) {
-          const isFocusOutsideWindow = getBoundingRect(focusedElement).bottom < 0;
-          if (!isFocusOutsideWindow) {
-            restoreFocus(focusedElement, selectionRange);
-          }
-        }
+      if (restoreAfterBestFitMode) {
+        restoreAfterBestFitMode();
       }
 
-      isColumnWidthsCorrected = this._correctColumnWidths(resultWidths, visibleColumns);
+      const isColumnWidthsCorrected = this._correctColumnWidths(resultWidths, visibleColumns);
 
       if (columnAutoWidth) {
-        normalizeWidthsByExpandColumns();
+        this._normalizeWidthsByExpandColumns(resultWidths, visibleColumns);
         if (this._needStretch()) {
           this._processStretch(resultWidths, visibleColumns);
         }
@@ -478,6 +465,21 @@ export class ResizingController extends modules.ViewController {
     return freeWidth / columnCountWithoutWidth;
   }
 
+  private readonly _normalizeWidthsByExpandColumns = (resultWidths, visibleColumns): void => {
+    const expandColumnIndex = visibleColumns.findIndex((column) => column.type === 'groupExpand');
+    const expandColumnWidth = resultWidths[expandColumnIndex];
+
+    if (!isDefined(expandColumnWidth)) {
+      return;
+    }
+
+    each(visibleColumns, (index, column) => {
+      if (column.type === 'groupExpand') {
+        resultWidths[index] = expandColumnWidth;
+      }
+    });
+  };
+
   /**
    * @extended: adaptivity
    */
@@ -487,7 +489,6 @@ export class ResizingController extends modules.ViewController {
     let hasPercentWidth = false;
     let hasAutoWidth = false;
     let isColumnWidthsCorrected = false;
-    const $element = that.component.$element();
     const hasWidth = that._hasWidth;
 
     for (i = 0; i < visibleColumns.length; i++) {
@@ -540,9 +541,7 @@ export class ResizingController extends modules.ViewController {
           if (hasWidth === false && !hasPercentWidth) {
             const borderWidth = gridCoreUtils.getComponentBorderWidth(this, $rowsViewElement);
 
-            that._maxWidth = totalWidth + scrollbarWidth + borderWidth;
-
-            $element.css('maxWidth', that._maxWidth);
+            that._maxWidth.set(totalWidth + scrollbarWidth + borderWidth);
           }
         }
       }
diff --git a/packages/devextreme/js/__internal/ui/popover/popover.ts b/packages/devextreme/js/__internal/ui/popover/popover.ts
index 6e5676cf2189..bf60b74ff3ab 100644
--- a/packages/devextreme/js/__internal/ui/popover/popover.ts
+++ b/packages/devextreme/js/__internal/ui/popover/popover.ts
@@ -200,7 +200,7 @@ class Popover<
       const { visible } = this.option();
 
       const overlayStack = this._overlayStack();
-      const isTopOverlay = overlayStack[overlayStack.length - 1] === this;
+      const isTopOverlay = overlayStack[overlayStack.length - 1] === this as unknown;
 
       if (normalizeKeyName(e) === ESC_KEY_NAME && visible && isTopOverlay) {
         // eslint-disable-next-line @typescript-eslint/no-floating-promises

From 3d602d34cd330568736218100c8f7809f64f67b2 Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Wed, 15 Jul 2026 22:46:50 +0300
Subject: [PATCH 02/11] fix(popover): remove unnecessary type assertion for
 overlay stack check

---
 packages/devextreme/js/__internal/ui/popover/popover.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/devextreme/js/__internal/ui/popover/popover.ts b/packages/devextreme/js/__internal/ui/popover/popover.ts
index bf60b74ff3ab..6e5676cf2189 100644
--- a/packages/devextreme/js/__internal/ui/popover/popover.ts
+++ b/packages/devextreme/js/__internal/ui/popover/popover.ts
@@ -200,7 +200,7 @@ class Popover<
       const { visible } = this.option();
 
       const overlayStack = this._overlayStack();
-      const isTopOverlay = overlayStack[overlayStack.length - 1] === this as unknown;
+      const isTopOverlay = overlayStack[overlayStack.length - 1] === this;
 
       if (normalizeKeyName(e) === ESC_KEY_NAME && visible && isTopOverlay) {
         // eslint-disable-next-line @typescript-eslint/no-floating-promises

From 9957424bc2281f4889aacb059871ebe9ec82c7c6 Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Wed, 15 Jul 2026 22:56:12 +0300
Subject: [PATCH 03/11] fix(m_utils): handle non-numeric selectionStart and
 selectionEnd values

---
 packages/devextreme/js/__internal/grids/grid_core/m_utils.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
index af9ca4fd1b3b..be482ce2fb82 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
@@ -572,8 +572,8 @@ export default {
     try {
       if (focusedElement) {
         return {
-          selectionStart: focusedElement.selectionStart,
-          selectionEnd: focusedElement.selectionEnd,
+          selectionStart: isNumeric(focusedElement.selectionStart) ? focusedElement.selectionStart : -1,
+          selectionEnd: isNumeric(focusedElement.selectionEnd) ? focusedElement.selectionEnd : -1,
           selectionDirection: focusedElement.selectionDirection ?? undefined,
         };
       }

From 32ad957e421a0b4a220a67ea863777e8349b93eb Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Wed, 15 Jul 2026 22:58:59 +0300
Subject: [PATCH 04/11] fix(grid_view): correct spacing in _synchronizeColumns
 method

---
 .../js/__internal/grids/grid_core/views/m_grid_view.ts          | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index 09460b162b88..88b9da1c35ed 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -382,7 +382,7 @@ export class ResizingController extends modules.ViewController {
     };
   }
 
-  private _synchronizeColumns():void {
+  private _synchronizeColumns(): void {
     const columnsController = this._columnsController;
     const visibleColumns = columnsController.getVisibleColumns();
     const columnAutoWidth = this.option('columnAutoWidth') as boolean;

From dfde56ef47d38229c6256679306977e1dd56698c Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Tue, 21 Jul 2026 18:08:05 +0300
Subject: [PATCH 05/11] fix(m_utils): remove selectionDirection from
 SelectionRange interface and related logic

---
 packages/devextreme/js/__internal/grids/grid_core/m_utils.ts | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
index be482ce2fb82..8dec78937234 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
@@ -73,7 +73,6 @@ export function isDateType(dataType: string | undefined): boolean {
 export interface SelectionRange {
   selectionStart: number;
   selectionEnd: number;
-  selectionDirection?: 'forward' | 'backward' | 'none';
 }
 
 const getIntervalSelector = function () {
@@ -574,7 +573,6 @@ export default {
         return {
           selectionStart: isNumeric(focusedElement.selectionStart) ? focusedElement.selectionStart : -1,
           selectionEnd: isNumeric(focusedElement.selectionEnd) ? focusedElement.selectionEnd : -1,
-          selectionDirection: focusedElement.selectionDirection ?? undefined,
         };
       }
     } catch (e) { /* empty */ }
@@ -588,7 +586,7 @@ export default {
   setSelectionRange(focusedElement, selectionRange: SelectionRange): void {
     try {
       if (focusedElement && focusedElement.setSelectionRange && selectionRange.selectionStart >= 0 && selectionRange.selectionEnd >= 0) {
-        focusedElement.setSelectionRange(selectionRange.selectionStart, selectionRange.selectionEnd, selectionRange.selectionDirection);
+        focusedElement.setSelectionRange(selectionRange.selectionStart, selectionRange.selectionEnd);
       }
     } catch (e) { /* empty */ }
   },

From 781388e0462d5be89d9a9e08dcfcd429bb6f817b Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Tue, 22 Sep 2026 14:30:13 +0300
Subject: [PATCH 06/11] Update after review

---
 ...normalize_widths_by_expand_columns.test.ts | 81 ++++++++++++++++++
 .../grids/grid_core/views/m_grid_view.ts      | 84 +++++++++++--------
 2 files changed, 128 insertions(+), 37 deletions(-)
 create mode 100644 packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts

diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts b/packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts
new file mode 100644
index 000000000000..ce9e39942abc
--- /dev/null
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts
@@ -0,0 +1,81 @@
+import { describe, expect, it } from '@jest/globals';
+
+import type { Column } from '../../columns_controller/types';
+import { ResizingController } from '../m_grid_view';
+
+type ColumnWidth = number | string | undefined;
+
+// NOTE: the method is private, so it is picked from the prototype to be tested in isolation.
+const resizingControllerPrototype = ResizingController.prototype as unknown as {
+  _normalizeWidthsByExpandColumns: (
+    resultWidths: ColumnWidth[],
+    visibleColumns: Column[],
+  ) => void;
+};
+
+const normalizeWidthsByExpandColumns = (
+  resultWidths: ColumnWidth[],
+  visibleColumns: Column[],
+): ColumnWidth[] => {
+  resizingControllerPrototype._normalizeWidthsByExpandColumns(resultWidths, visibleColumns);
+
+  return resultWidths;
+};
+
+const expandColumn = (): Column => ({ type: 'groupExpand', command: 'expand' } as Column);
+const dataColumn = (dataField: string): Column => ({ dataField } as Column);
+
+describe('ResizingController._normalizeWidthsByExpandColumns', () => {
+  it('leaves the widths as is when there are no expand columns', () => {
+    const columns = [dataColumn('a'), dataColumn('b')];
+
+    expect(normalizeWidthsByExpandColumns([100, 200], columns)).toEqual([100, 200]);
+  });
+
+  it('leaves the widths as is when there is a single expand column', () => {
+    const columns = [expandColumn(), dataColumn('a')];
+
+    expect(normalizeWidthsByExpandColumns([30, 200], columns)).toEqual([30, 200]);
+  });
+
+  // NOTE: all groupExpand columns share a single column id (command:expand), so the width
+  // of the last one is the value that _setVisibleWidths actually applies to all of them.
+  it('applies the width of the LAST expand column to every expand column', () => {
+    const columns = [expandColumn(), expandColumn(), dataColumn('a')];
+
+    expect(normalizeWidthsByExpandColumns([21, 30, 200], columns)).toEqual([30, 30, 200]);
+  });
+
+  it('normalizes expand columns that are not adjacent to each other', () => {
+    const columns = [
+      dataColumn('a'),
+      expandColumn(),
+      dataColumn('b'),
+      expandColumn(),
+      dataColumn('c'),
+    ];
+
+    expect(normalizeWidthsByExpandColumns([100, 21, 200, 30, 300], columns))
+      .toEqual([100, 30, 200, 30, 300]);
+  });
+
+  it('ignores the detailExpand column', () => {
+    const columns = [
+      { type: 'detailExpand', command: 'expand' } as Column,
+      expandColumn(),
+      expandColumn(),
+    ];
+
+    expect(normalizeWidthsByExpandColumns([15, 21, 30], columns)).toEqual([15, 30, 30]);
+  });
+
+  // NOTE: a falsy width means the column could not be measured (e.g. the grid is hidden).
+  it.each([
+    ['zero', 0],
+    ['undefined', undefined],
+  ])('keeps the measured widths when the last expand column width is %s', (_, width) => {
+    const columns = [expandColumn(), expandColumn(), dataColumn('a')];
+
+    expect(normalizeWidthsByExpandColumns([21, width, 200], columns)).toEqual([21, width, 200]);
+  });
+});
diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index 69e810804bed..465687847a71 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -21,7 +21,9 @@ import { A11yStatusContainerComponent } from '@ts/grids/grid_core/views/a11y_sta
 import type { FooterView } from '../../data_grid/summary/m_summary';
 import type { AdaptiveColumnsController } from '../adaptivity/m_adaptivity';
 import type { ColumnHeadersView } from '../column_headers/m_column_headers';
+import { GROUP_COMMAND_COLUMN_NAME } from '../columns_controller/const';
 import type { ColumnsController } from '../columns_controller/m_columns_controller';
+import type { Column } from '../columns_controller/types';
 import type { DataController } from '../data_controller/data_controller';
 import type { DataChange } from '../data_controller/types';
 import type { DataSourceController } from '../data_source/data_source_controller';
@@ -37,6 +39,8 @@ const GROUP_ROW_SELECTOR = 'tr.dx-group-row';
 
 const HIDDEN_COLUMNS_WIDTH = 'adaptiveHidden';
 
+type ColumnWidth = number | string | undefined;
+
 const VIEW_NAMES = [
   'columnsSeparatorView',
   'blockSeparatorView',
@@ -86,12 +90,6 @@ const restoreFocus = (focusedElement: Element, selectionRange: SelectionRange):
   gridCoreUtils.setSelectionRange(focusedElement, selectionRange);
 };
 
-interface MaxWidthController {
-  isModified: boolean;
-  set: (value: number) => void;
-  clear: () => void;
-}
-
 export class ResizingController extends modules.ViewController {
   private _refreshSizesHandler: any;
 
@@ -131,25 +129,7 @@ export class ResizingController extends modules.ViewController {
 
   public resizeCompleted!: Callback;
 
-  private readonly _maxWidth: MaxWidthController = {
-    isModified: false,
-    set: (value): void => {
-      const $element = this.component.$element();
-
-      this._maxWidth.isModified = true;
-      $element.css('maxWidth', value);
-    },
-    clear: (): void => {
-      const $element = this.component.$element();
-
-      if (!this._maxWidth.isModified || !$element || !$element.get(0)) {
-        return;
-      }
-
-      this._maxWidth.isModified = false;
-      $element[0].style.maxWidth = '';
-    },
-  };
+  private _isMaxWidthSet = false;
 
   protected callbackNames() {
     return ['resizeCompleted'];
@@ -369,6 +349,25 @@ export class ResizingController extends modules.ViewController {
     }
   }
 
+  private _setMaxWidth(value: number): void {
+    this._isMaxWidthSet = true;
+    this.component.$element().css('maxWidth', value);
+  }
+
+  private _clearMaxWidth(): void {
+    if (!this._isMaxWidthSet) {
+      return;
+    }
+
+    this._isMaxWidthSet = false;
+
+    const element = this.component.$element().get(0) as HTMLElement | undefined;
+
+    if (element) {
+      element.style.maxWidth = '';
+    }
+  }
+
   private _enableTemporaryBestFitMode(): () => void {
     const $element = this.component.$element();
     const focusedElement = domAdapter.getActiveElement($element.get(0) as HTMLElement | null);
@@ -401,11 +400,11 @@ export class ResizingController extends modules.ViewController {
     this._toggleContentMinHeight(this._hasHeight); // T1047239, T1270354
     this._setVisibleWidths(visibleColumns, []);
     const restoreAfterBestFitMode = needBestFit && this._enableTemporaryBestFitMode();
-    this._maxWidth.clear();
+    this._clearMaxWidth();
 
     // eslint-disable-next-line @typescript-eslint/no-floating-promises
     deferUpdate(() => {
-      let resultWidths: (number | string | undefined)[] = [];
+      let resultWidths: ColumnWidth[] = [];
 
       if (needBestFit || hasMinWidth) {
         resultWidths = this._getBestFitWidths();
@@ -472,20 +471,31 @@ export class ResizingController extends modules.ViewController {
     return freeWidth / columnCountWithoutWidth;
   }
 
-  private readonly _normalizeWidthsByExpandColumns = (resultWidths, visibleColumns): void => {
-    const expandColumnIndex = visibleColumns.findIndex((column) => column.type === 'groupExpand');
-    const expandColumnWidth = resultWidths[expandColumnIndex];
+  private _normalizeWidthsByExpandColumns(
+    resultWidths: ColumnWidth[],
+    visibleColumns: Column[],
+  ): void {
+    const expandColumnIndexes = visibleColumns.reduce<number[]>(
+      (indexes, column, index) => (
+        column.type === GROUP_COMMAND_COLUMN_NAME ? [...indexes, index] : indexes
+      ),
+      [],
+    );
+
+    // NOTE: all groupExpand columns share a single column id (command:expand),
+    // so the width of the last one is what actually gets applied to all of them.
+    const expandColumnWidth = resultWidths[expandColumnIndexes.at(-1) ?? -1];
 
-    if (!isDefined(expandColumnWidth)) {
+    // NOTE: a falsy width means the column could not be measured (e.g. the grid is hidden),
+    // in that case the measured widths are kept as is.
+    if (!expandColumnWidth) {
       return;
     }
 
-    each(visibleColumns, (index, column) => {
-      if (column.type === 'groupExpand') {
-        resultWidths[index] = expandColumnWidth;
-      }
+    expandColumnIndexes.forEach((index) => {
+      resultWidths[index] = expandColumnWidth;
     });
-  };
+  }
 
   /**
    * @extended: adaptivity
@@ -548,7 +558,7 @@ export class ResizingController extends modules.ViewController {
           if (hasWidth === false && !hasPercentWidth) {
             const borderWidth = gridCoreUtils.getComponentBorderWidth(this, $rowsViewElement);
 
-            that._maxWidth.set(totalWidth + scrollbarWidth + borderWidth);
+            that._setMaxWidth(totalWidth + scrollbarWidth + borderWidth);
           }
         }
       }

From 1312c25ea13ff8a5e4cccbc19d4b27ab86d8b0f6 Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Tue, 22 Sep 2026 14:56:00 +0300
Subject: [PATCH 07/11] refactor(ResizingController): simplify expand column
 width calculation

---
 .../grids/grid_core/views/m_grid_view.ts      | 26 ++++++++++---------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index 465687847a71..6e5fafd88030 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -475,25 +475,27 @@ export class ResizingController extends modules.ViewController {
     resultWidths: ColumnWidth[],
     visibleColumns: Column[],
   ): void {
-    const expandColumnIndexes = visibleColumns.reduce<number[]>(
-      (indexes, column, index) => (
-        column.type === GROUP_COMMAND_COLUMN_NAME ? [...indexes, index] : indexes
-      ),
-      [],
+    const isExpandColumn = (column: Column): boolean => column.type === GROUP_COMMAND_COLUMN_NAME;
+
+    const lastExpandColumnIndex = visibleColumns.reduce(
+      (result, column, index) => (isExpandColumn(column) ? index : result),
+      -1,
     );
 
-    // NOTE: all groupExpand columns share a single column id (command:expand),
-    // so the width of the last one is what actually gets applied to all of them.
-    const expandColumnWidth = resultWidths[expandColumnIndexes.at(-1) ?? -1];
+    if (lastExpandColumnIndex < 0) {
+      return;
+    }
+
+    const expandColumnWidth = resultWidths[lastExpandColumnIndex];
 
-    // NOTE: a falsy width means the column could not be measured (e.g. the grid is hidden),
-    // in that case the measured widths are kept as is.
     if (!expandColumnWidth) {
       return;
     }
 
-    expandColumnIndexes.forEach((index) => {
-      resultWidths[index] = expandColumnWidth;
+    visibleColumns.forEach((column, index) => {
+      if (isExpandColumn(column)) {
+        resultWidths[index] = expandColumnWidth;
+      }
     });
   }
 

From e86dc6d31ae6d53fc357cefbd1ed9aa2d6771b5f Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Tue, 22 Sep 2026 15:25:32 +0300
Subject: [PATCH 08/11] refactor(ResizingController): remove redundant comment
 before measurement preparation

---
 .../js/__internal/grids/grid_core/views/m_grid_view.ts           | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index 6e5fafd88030..ddf0012c961b 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -396,7 +396,6 @@ export class ResizingController extends modules.ViewController {
     const needBestFit = this._needBestFit() || visibleColumns.some((column) => column.width === 'auto');
     const hasMinWidth = visibleColumns.some((column) => !!column.minWidth);
 
-    // Prepare for measurement
     this._toggleContentMinHeight(this._hasHeight); // T1047239, T1270354
     this._setVisibleWidths(visibleColumns, []);
     const restoreAfterBestFitMode = needBestFit && this._enableTemporaryBestFitMode();

From 57b55a3888f7a43d9c2ff9af00e3655814a350e4 Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Wed, 23 Sep 2026 19:43:09 +0300
Subject: [PATCH 09/11] feat(SelectionRange): add SelectionRange interface and
 update imports

---
 .../js/__internal/grids/grid_core/m_types.ts       |  5 +++++
 .../js/__internal/grids/grid_core/m_utils.ts       |  7 +------
 .../grids/grid_core/views/m_grid_view.ts           | 14 +++++++-------
 .../js/__internal/grids/grid_core/views/types.ts   |  2 ++
 4 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/m_types.ts b/packages/devextreme/js/__internal/grids/grid_core/m_types.ts
index 529353610025..242bdcc824c6 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/m_types.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/m_types.ts
@@ -34,6 +34,11 @@ export interface Coordinates {
   y: number;
 }
 
+export interface SelectionRange {
+  selectionStart: number;
+  selectionEnd: number;
+}
+
 // todo: move to upper .d.ts
 type OptionsMethod<TOptions> = (() => TOptions)
   & ((options: TOptions) => void)
diff --git a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
index fb8fbb4840a9..ca64420e7f46 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/m_utils.ts
@@ -23,7 +23,7 @@ import sharedFiltering from '@js/ui/shared/filtering';
 import { getGlobalFormatByDataType } from '@ts/core/global_format_config';
 import { isNumeric } from '@ts/core/utils/m_type';
 import type { Column } from '@ts/grids/grid_core/columns_controller/types';
-import type { ColumnPoint } from '@ts/grids/grid_core/m_types';
+import type { ColumnPoint, SelectionRange } from '@ts/grids/grid_core/m_types';
 
 import { AI_COLUMN_NAME } from './ai_column/const';
 import type DataSourceAdapter from './data_source_adapter/m_data_source_adapter';
@@ -72,11 +72,6 @@ export function isDateType(dataType: string | undefined): boolean {
   return dataType === 'date' || dataType === 'datetime';
 }
 
-export interface SelectionRange {
-  selectionStart: number;
-  selectionEnd: number;
-}
-
 const getIntervalSelector = function () {
   const data = arguments[1];
   const value = this.calculateCellValue(data);
diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index ddf0012c961b..b8e9d434813c 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -28,8 +28,10 @@ import type { DataController } from '../data_controller/data_controller';
 import type { DataChange } from '../data_controller/types';
 import type { DataSourceController } from '../data_source/data_source_controller';
 import modules from '../m_modules';
-import gridCoreUtils, { type SelectionRange } from '../m_utils';
+import type { SelectionRange } from '../m_types';
+import gridCoreUtils from '../m_utils';
 import type { RowsView } from './m_rows_view';
+import type { ColumnWidth } from './types';
 
 const BORDERS_CLASS = 'borders';
 const TABLE_FIXED_CLASS = 'table-fixed';
@@ -39,8 +41,6 @@ const GROUP_ROW_SELECTOR = 'tr.dx-group-row';
 
 const HIDDEN_COLUMNS_WIDTH = 'adaptiveHidden';
 
-type ColumnWidth = number | string | undefined;
-
 const VIEW_NAMES = [
   'columnsSeparatorView',
   'blockSeparatorView',
@@ -129,7 +129,7 @@ export class ResizingController extends modules.ViewController {
 
   public resizeCompleted!: Callback;
 
-  private _isMaxWidthSet = false;
+  private isMaxWidthSet = false;
 
   protected callbackNames() {
     return ['resizeCompleted'];
@@ -350,16 +350,16 @@ export class ResizingController extends modules.ViewController {
   }
 
   private _setMaxWidth(value: number): void {
-    this._isMaxWidthSet = true;
+    this.isMaxWidthSet = true;
     this.component.$element().css('maxWidth', value);
   }
 
   private _clearMaxWidth(): void {
-    if (!this._isMaxWidthSet) {
+    if (!this.isMaxWidthSet) {
       return;
     }
 
-    this._isMaxWidthSet = false;
+    this.isMaxWidthSet = false;
 
     const element = this.component.$element().get(0) as HTMLElement | undefined;
 
diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/types.ts b/packages/devextreme/js/__internal/grids/grid_core/views/types.ts
index a2f0306d5705..485c13a4f5ed 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/types.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/types.ts
@@ -6,3 +6,5 @@ export type RowsViewScrollEvent = Partial<ScrollEventInfo<dxScrollable>> & {
   scrollOffset: { top: number; left: number };
   forceUpdateScrollPosition?: boolean;
 };
+
+export type ColumnWidth = number | string | undefined;

From 9f8361666d0203f56bc1a8cf2a6eb264439c44f7 Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Wed, 23 Sep 2026 20:09:51 +0300
Subject: [PATCH 10/11] refactor(ResizingController): rename private methods
 for consistency

---
 ...d_view.normalize_widths_by_expand_columns.test.ts |  6 +++---
 .../__internal/grids/grid_core/views/m_grid_view.ts  | 12 ++++++------
 .../dataGrid.resizing.tests.js                       | 10 +++++-----
 .../filtering.integration.tests.js                   |  2 +-
 4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts b/packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts
index ce9e39942abc..16b8b9c247de 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/__tests__/grid_view.normalize_widths_by_expand_columns.test.ts
@@ -7,7 +7,7 @@ type ColumnWidth = number | string | undefined;
 
 // NOTE: the method is private, so it is picked from the prototype to be tested in isolation.
 const resizingControllerPrototype = ResizingController.prototype as unknown as {
-  _normalizeWidthsByExpandColumns: (
+  normalizeWidthsByExpandColumns: (
     resultWidths: ColumnWidth[],
     visibleColumns: Column[],
   ) => void;
@@ -17,7 +17,7 @@ const normalizeWidthsByExpandColumns = (
   resultWidths: ColumnWidth[],
   visibleColumns: Column[],
 ): ColumnWidth[] => {
-  resizingControllerPrototype._normalizeWidthsByExpandColumns(resultWidths, visibleColumns);
+  resizingControllerPrototype.normalizeWidthsByExpandColumns(resultWidths, visibleColumns);
 
   return resultWidths;
 };
@@ -25,7 +25,7 @@ const normalizeWidthsByExpandColumns = (
 const expandColumn = (): Column => ({ type: 'groupExpand', command: 'expand' } as Column);
 const dataColumn = (dataField: string): Column => ({ dataField } as Column);
 
-describe('ResizingController._normalizeWidthsByExpandColumns', () => {
+describe('ResizingController.normalizeWidthsByExpandColumns', () => {
   it('leaves the widths as is when there are no expand columns', () => {
     const columns = [dataColumn('a'), dataColumn('b')];
 
diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index b8e9d434813c..de412b8b9c3a 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -368,7 +368,7 @@ export class ResizingController extends modules.ViewController {
     }
   }
 
-  private _enableTemporaryBestFitMode(): () => void {
+  private enableTemporaryBestFitMode(): () => void {
     const $element = this.component.$element();
     const focusedElement = domAdapter.getActiveElement($element.get(0) as HTMLElement | null);
     const selectionRange = gridCoreUtils.getSelectionRange(focusedElement);
@@ -388,7 +388,7 @@ export class ResizingController extends modules.ViewController {
     };
   }
 
-  private _synchronizeColumns(): void {
+  private synchronizeColumns(): void {
     const columnsController = this._columnsController;
     const visibleColumns = columnsController.getVisibleColumns();
     const columnAutoWidth = this.option('columnAutoWidth') as boolean;
@@ -398,7 +398,7 @@ export class ResizingController extends modules.ViewController {
 
     this._toggleContentMinHeight(this._hasHeight); // T1047239, T1270354
     this._setVisibleWidths(visibleColumns, []);
-    const restoreAfterBestFitMode = needBestFit && this._enableTemporaryBestFitMode();
+    const restoreAfterBestFitMode = needBestFit && this.enableTemporaryBestFitMode();
     this._clearMaxWidth();
 
     // eslint-disable-next-line @typescript-eslint/no-floating-promises
@@ -432,7 +432,7 @@ export class ResizingController extends modules.ViewController {
       const isColumnWidthsCorrected = this._correctColumnWidths(resultWidths, visibleColumns);
 
       if (columnAutoWidth) {
-        this._normalizeWidthsByExpandColumns(resultWidths, visibleColumns);
+        this.normalizeWidthsByExpandColumns(resultWidths, visibleColumns);
         if (this._needStretch()) {
           this._processStretch(resultWidths, visibleColumns);
         }
@@ -470,7 +470,7 @@ export class ResizingController extends modules.ViewController {
     return freeWidth / columnCountWithoutWidth;
   }
 
-  private _normalizeWidthsByExpandColumns(
+  private normalizeWidthsByExpandColumns(
     resultWidths: ColumnWidth[],
     visibleColumns: Column[],
   ): void {
@@ -733,7 +733,7 @@ export class ResizingController extends modules.ViewController {
     when(prevResult).always(() => {
       deferRender(() => {
         if (that._dataController.isLoaded()) {
-          that._synchronizeColumns();
+          that.synchronizeColumns();
         }
         // IE11
         that._resetGroupElementHeight();
diff --git a/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/dataGrid.resizing.tests.js b/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/dataGrid.resizing.tests.js
index 1aac2811455c..5ac896cb34b5 100644
--- a/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/dataGrid.resizing.tests.js
+++ b/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/dataGrid.resizing.tests.js
@@ -1230,13 +1230,13 @@ QUnit.module('API Methods', baseModuleConfig, () => {
             dataSource: [{ field1: 1, field2: 2, field3: 3 }]
         });
 
-        sinon.spy(dataGrid.getController('resizing'), '_synchronizeColumns');
+        sinon.spy(dataGrid.getController('resizing'), 'synchronizeColumns');
 
         // act
         resizeCallbacks.fire();
 
         // assert
-        assert.equal(dataGrid.getController('resizing')._synchronizeColumns.callCount, 0, 'synchronizeColumns is not called');
+        assert.equal(dataGrid.getController('resizing').synchronizeColumns.callCount, 0, 'synchronizeColumns is not called');
 
 
         // act
@@ -1244,7 +1244,7 @@ QUnit.module('API Methods', baseModuleConfig, () => {
         resizeCallbacks.fire();
 
         // assert
-        assert.equal(dataGrid.getController('resizing')._synchronizeColumns.callCount, 1, 'synchronizeColumns is called');
+        assert.equal(dataGrid.getController('resizing').synchronizeColumns.callCount, 1, 'synchronizeColumns is called');
     });
 
     // T372519
@@ -1264,7 +1264,7 @@ QUnit.module('API Methods', baseModuleConfig, () => {
 
         const rowsViewHeight = $('#dataGrid .dx-datagrid-rowsview').height();
 
-        sinon.spy(dataGrid.getController('resizing'), '_synchronizeColumns');
+        sinon.spy(dataGrid.getController('resizing'), 'synchronizeColumns');
 
         // act
         $('#qunit-fixture').hide();
@@ -1272,7 +1272,7 @@ QUnit.module('API Methods', baseModuleConfig, () => {
         $('#qunit-fixture').show();
 
         // assert
-        assert.equal(dataGrid.getController('resizing')._synchronizeColumns.callCount, 0, 'synchronizeColumns is not called');
+        assert.equal(dataGrid.getController('resizing').synchronizeColumns.callCount, 0, 'synchronizeColumns is not called');
         assert.equal($('#dataGrid .dx-datagrid-rowsview').height(), rowsViewHeight, 'rowsView height is not changed');
     });
 
diff --git a/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/filtering.integration.tests.js b/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/filtering.integration.tests.js
index 76d6fe2ed6e4..181377bcf6f9 100644
--- a/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/filtering.integration.tests.js
+++ b/packages/devextreme/testing/tests/DevExpress.ui.widgets.dataGrid/filtering.integration.tests.js
@@ -194,7 +194,7 @@ QUnit.module('Initialization', baseModuleConfig, () => {
         assert.equal(dataGrid.getVisibleRows().length, 1, 'rows are filtered');
     });
 
-    QUnit.testInActiveWindow('Filter row editor should have focus after _synchronizeColumns (T638737)', function(assert) {
+    QUnit.testInActiveWindow('Filter row editor should have focus after synchronizeColumns (T638737)', function(assert) {
         $('#qunit-fixture').css('position', 'static');
         // arrange, act
         const dataGrid = createDataGrid({

From cdce32f8ff150d43f2f8e280aa445ba438c14005 Mon Sep 17 00:00:00 2001
From: Eugen Zha <eugen.zha@gmail.com>
Date: Wed, 23 Sep 2026 20:27:39 +0300
Subject: [PATCH 11/11] refactor(ResizingController): rename private method
 _setMaxWidth to setMaxWidth for consistency

---
 .../js/__internal/grids/grid_core/views/m_grid_view.ts        | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
index de412b8b9c3a..c30560361fd2 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/views/m_grid_view.ts
@@ -349,7 +349,7 @@ export class ResizingController extends modules.ViewController {
     }
   }
 
-  private _setMaxWidth(value: number): void {
+  private setMaxWidth(value: number): void {
     this.isMaxWidthSet = true;
     this.component.$element().css('maxWidth', value);
   }
@@ -559,7 +559,7 @@ export class ResizingController extends modules.ViewController {
           if (hasWidth === false && !hasPercentWidth) {
             const borderWidth = gridCoreUtils.getComponentBorderWidth(this, $rowsViewElement);
 
-            that._setMaxWidth(totalWidth + scrollbarWidth + borderWidth);
+            that.setMaxWidth(totalWidth + scrollbarWidth + borderWidth);
           }
         }
       }