From aefc4ab423c0c836beb0da9f75e1dbf35a0d1d0b Mon Sep 17 00:00:00 2001
From: Rajat <robertdoweny2301@gmail.com>
Date: Fri, 10 Jan 2025 18:04:25 +0530
Subject: [PATCH 1/3] fix focus

---
 .../keyboardNavigation/useGridKeyboardNavigation.ts    | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts b/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts
index 45cb7e7df94c1..2965f6d16e9ce 100644
--- a/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts
+++ b/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts
@@ -176,13 +176,13 @@ export const useGridKeyboardNavigation = (
 
       switch (event.key) {
         case 'ArrowDown': {
-          if (firstRowIndexInPage !== null) {
-            if (headerFilteringEnabled) {
-              goToHeaderFilter(colIndexBefore, event);
-            } else {
+          if (headerFilteringEnabled) {
+            goToHeaderFilter(colIndexBefore, event);
+          } else {
+            if (firstRowIndexInPage !== null)
               goToCell(colIndexBefore, getRowIdFromIndex(firstRowIndexInPage));
-            }
           }
+
           break;
         }
 

From 03422985d01bd98cb5ed4ed1653255a3ce790a10 Mon Sep 17 00:00:00 2001
From: Rajat <robertdoweny2301@gmail.com>
Date: Sat, 11 Jan 2025 12:40:59 +0530
Subject: [PATCH 2/3] lint

---
 .../features/keyboardNavigation/useGridKeyboardNavigation.ts | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts b/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts
index 2965f6d16e9ce..179bcc0cd405f 100644
--- a/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts
+++ b/packages/x-data-grid/src/hooks/features/keyboardNavigation/useGridKeyboardNavigation.ts
@@ -178,9 +178,8 @@ export const useGridKeyboardNavigation = (
         case 'ArrowDown': {
           if (headerFilteringEnabled) {
             goToHeaderFilter(colIndexBefore, event);
-          } else {
-            if (firstRowIndexInPage !== null)
-              goToCell(colIndexBefore, getRowIdFromIndex(firstRowIndexInPage));
+          } else if (firstRowIndexInPage !== null) {
+            goToCell(colIndexBefore, getRowIdFromIndex(firstRowIndexInPage));
           }
 
           break;

From e9fc10020f6319e5108ef7c219be88d8144b6177 Mon Sep 17 00:00:00 2001
From: Bilal Shafi <bilalshafidev@gmail.com>
Date: Tue, 28 Jan 2025 15:04:30 +0500
Subject: [PATCH 3/3] Add test

---
 .../src/tests/filtering.DataGridPro.test.tsx  | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/packages/x-data-grid-pro/src/tests/filtering.DataGridPro.test.tsx b/packages/x-data-grid-pro/src/tests/filtering.DataGridPro.test.tsx
index 6a45a97d1977b..8ec4844de6909 100644
--- a/packages/x-data-grid-pro/src/tests/filtering.DataGridPro.test.tsx
+++ b/packages/x-data-grid-pro/src/tests/filtering.DataGridPro.test.tsx
@@ -1262,6 +1262,33 @@ describe('<DataGridPro /> - Filter', () => {
       await waitFor(() => expect(getColumnValues(0)).to.deep.equal(['100', '1,000']));
       expect(changeSpy.lastCall.args[0].items[0].value).to.equal(10); // 0.1e2
     });
+
+    it('should allow to navigate to the header filter cell when there are no rows', async () => {
+      clock.restore();
+      const { user } = render(
+        <TestCase
+          headerFilters
+          initialState={{
+            filter: {
+              filterModel: {
+                items: [
+                  {
+                    field: 'brand',
+                    operator: 'contains',
+                    value: 'abc',
+                  },
+                ],
+              },
+            },
+          }}
+        />,
+      );
+      const headerCell = getColumnHeaderCell(0, 0);
+      const filterCell = getColumnHeaderCell(0, 1);
+      await user.click(headerCell);
+      await user.keyboard('{ArrowDown}');
+      expect(filterCell).toHaveFocus();
+    });
   });
 
   describe('Read-only filters', () => {