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diff --git a/e2e/testcafe-devextreme/tests/scheduler/common/layout/timeIndication/etalons/shader-virtual-scrolling-week-start (fluent.blue.light).png b/e2e/testcafe-devextreme/tests/scheduler/common/layout/timeIndication/etalons/shader-virtual-scrolling-week-start (fluent.blue.light).png
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diff --git a/e2e/testcafe-devextreme/tests/scheduler/common/layout/timeIndication/shader-virtual-scrolling.ts b/e2e/testcafe-devextreme/tests/scheduler/common/layout/timeIndication/shader-virtual-scrolling.ts
new file mode 100644
index 000000000000..1eccf9e7c6fc
--- /dev/null
+++ b/e2e/testcafe-devextreme/tests/scheduler/common/layout/timeIndication/shader-virtual-scrolling.ts
@@ -0,0 +1,72 @@
+import { createScreenshotsComparer } from 'devextreme-screenshot-comparer';
+import Scheduler from 'devextreme-testcafe-models/scheduler';
+import { insertStylesheetRulesToPage } from '../../../../../helpers/domUtils';
+import { createWidget } from '../../../../../helpers/createWidget';
+import url from '../../../../../helpers/getPageUrl';
+import { testScreenshot } from '../../../../../helpers/themeUtils';
+
+fixture.disablePageReloads`Scheduler: Current Time Indication: Shader with Virtual Scrolling`
+  .page(url(__dirname, '../../../../container.html'))
+  .beforeEach(async (t) => {
+    await t.resizeWindow(2560, 600);
+  });
+
+const style = `
+.dx-scheduler-date-time-shader-top::before,
+.dx-scheduler-date-time-shader-bottom::before,
+.dx-scheduler-timeline .dx-scheduler-date-time-shader::before,
+.dx-scheduler-date-time-shader-all-day {
+  background-color: red !important;
+}`;
+
+const resources = [
+  { text: 'Room 1', id: 1, color: '#cb6bb2' },
+  { text: 'Room 2', id: 2, color: '#56ca85' },
+  { text: 'Room 3', id: 3, color: '#1e90ff' },
+  { text: 'Room 4', id: 4, color: '#ff9747' },
+  { text: 'Room 5', id: 5, color: '#ff6a00' },
+  { text: 'Room 6', id: 6, color: '#ffc0cb' },
+];
+
+test('Shader should have correct width and left positions when scrolled to last groups with virtual scrolling (T1310524)', async (t) => {
+  const scheduler = new Scheduler('#container');
+  const { takeScreenshot, compareResults } = createScreenshotsComparer(t);
+
+  await scheduler.option('width', 2560);
+
+  await testScreenshot(
+    t,
+    takeScreenshot,
+    'shader-virtual-scrolling-week-start.png',
+    { element: scheduler.element },
+  );
+
+  await scheduler.scrollTo(new Date(2025, 9, 15, 17, 30), { roomId: 6 });
+
+  await testScreenshot(
+    t,
+    takeScreenshot,
+    'shader-virtual-scrolling-week-end.png',
+    { element: scheduler.element },
+  );
+
+  await t.expect(compareResults.isValid())
+    .ok(compareResults.errorMessages());
+}).before(async () => {
+  await insertStylesheetRulesToPage(style);
+
+  await createWidget('dxScheduler', {
+    dataSource: [],
+    currentView: 'week',
+    views: ['week'],
+    groups: ['roomId'],
+    resources: [{ fieldExpr: 'roomId', dataSource: resources, label: 'Room' }],
+    startDayHour: 8,
+    endDayHour: 18,
+    currentDate: new Date(2025, 9, 15),
+    height: 400,
+    width: 800,
+    shadeUntilCurrentTime: true,
+    scrolling: { mode: 'virtual' },
+  });
+});
diff --git a/packages/devextreme/js/__internal/scheduler/__tests__/workspace.test.ts b/packages/devextreme/js/__internal/scheduler/__tests__/workspace.test.ts
new file mode 100644
index 000000000000..2721336bba4f
--- /dev/null
+++ b/packages/devextreme/js/__internal/scheduler/__tests__/workspace.test.ts
@@ -0,0 +1,71 @@
+import {
+  afterEach, beforeEach, describe, expect, it,
+} from '@jest/globals';
+import $ from '@js/core/renderer';
+
+import fx from '../../../common/core/animation/fx';
+import { createScheduler } from './__mock__/create_scheduler';
+import { setupSchedulerTestEnvironment } from './__mock__/m_mock_scheduler';
+
+const CLASSES = {
+  scheduler: 'dx-scheduler',
+  workSpace: 'dx-scheduler-work-space',
+  shaderTop: 'dx-scheduler-date-time-shader-top',
+};
+
+describe('Workspace', () => {
+  beforeEach(() => {
+    fx.off = true;
+    setupSchedulerTestEnvironment({ height: 600 });
+  });
+
+  afterEach(() => {
+    const $scheduler = $(document.querySelector(`.${CLASSES.scheduler}`));
+    // @ts-expect-error
+    $scheduler.dxScheduler('dispose');
+    document.body.innerHTML = '';
+    fx.off = false;
+  });
+
+  it('should use group 0 width as fallback when groups are not rendered due to virtual scrolling (T1310524)', async () => {
+    const resources = [
+      { text: 'Room 1', id: 1, color: '#cb6bb2' },
+      { text: 'Room 2', id: 2, color: '#56ca85' },
+      { text: 'Room 3', id: 3, color: '#1e90ff' },
+      { text: 'Room 4', id: 4, color: '#ff9747' },
+      { text: 'Room 5', id: 5, color: '#ff6a00' },
+      { text: 'Room 6', id: 6, color: '#ffc0cb' },
+    ];
+
+    const { scheduler } = await createScheduler({
+      currentView: 'week',
+      views: ['week'],
+      groups: ['roomId'],
+      resources: [{ fieldExpr: 'roomId', dataSource: resources, label: 'Room' }],
+      dataSource: [
+        {
+          text: 'Meeting 1', startDate: new Date(2025, 9, 15, 9), endDate: new Date(2025, 9, 15, 10), roomId: 1,
+        },
+        {
+          text: 'Meeting 2', startDate: new Date(2025, 9, 15, 9), endDate: new Date(2025, 9, 15, 10), roomId: 4,
+        },
+      ],
+      startDayHour: 8,
+      endDayHour: 18,
+      currentDate: new Date(2025, 9, 15),
+      height: 400,
+      shadeUntilCurrentTime: true,
+      scrolling: { mode: 'virtual' },
+    });
+
+    const workSpace = scheduler.getWorkSpace();
+    const cellCount = workSpace._getCellCount();
+    const lastGroupWidth = workSpace.getRoundedCellWidth(
+      resources.length - 1,
+      (resources.length - 1) * cellCount,
+      cellCount,
+    );
+
+    expect(lastGroupWidth).toBeGreaterThan(0);
+  });
+});
diff --git a/packages/devextreme/js/__internal/scheduler/workspaces/m_work_space.ts b/packages/devextreme/js/__internal/scheduler/workspaces/m_work_space.ts
index c1649f57b664..a986cde507e0 100644
--- a/packages/devextreme/js/__internal/scheduler/workspaces/m_work_space.ts
+++ b/packages/devextreme/js/__internal/scheduler/workspaces/m_work_space.ts
@@ -1579,13 +1579,24 @@ class SchedulerWorkSpace extends Widget<WorkspaceOptionsInternal> {
       startIndex = totalCellCount;
     }
 
+    let foundElements = 0;
     for (let i = startIndex; i < totalCellCount + cellCount; i++) {
       const element = $($cells).eq(i).get(0);
       const elementWidth = element ? getBoundingRect(element).width : 0;
       width += elementWidth;
+      if (element) {
+        foundElements++;
+      }
     }
 
-    return width / (totalCellCount + cellCount - startIndex);
+    const divisor = totalCellCount + cellCount - startIndex;
+    let result = width / divisor;
+
+    if ((result === 0 || foundElements < cellCount) && groupIndex > 0) {
+      result = this.getRoundedCellWidth(0, 0, cellCount);
+    }
+
+    return result;
   }
 
   // Mappings