From a2796822949e4200d5e46c46d2cd608502f55efe Mon Sep 17 00:00:00 2001
From: Nicolas Stepien <stepien.nicolas@gmail.com>
Date: Mon, 5 Oct 2026 00:12:47 +0100
Subject: [PATCH] TreeDataGrid: focus the parent row on ArrowLeft

Pressing ArrowLeft on a collapsed child group made the parent group row
active without moving focus to it, leaving focus on the child row.
Also fix two comments that described the select/unselect branches the
wrong way round.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
---
 src/TreeDataGrid.tsx               | 6 +++---
 test/browser/TreeDataGrid.test.tsx | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/TreeDataGrid.tsx b/src/TreeDataGrid.tsx
index 8f9a85d639..d88bad6b18 100644
--- a/src/TreeDataGrid.tsx
+++ b/src/TreeDataGrid.tsx
@@ -273,7 +273,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
       const key = rowKeyGetter(row);
       if (selectedRows?.has(key) && !newSelectedRows.has(key)) {
         if (isGroupRow(row)) {
-          // select all children if the parent row is selected
+          // unselect all children if the parent row is unselected
           for (const cr of row.childRows) {
             newRawSelectedRows.delete(rawRowKeyGetter(cr));
           }
@@ -282,7 +282,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
         }
       } else if (!selectedRows?.has(key) && newSelectedRows.has(key)) {
         if (isGroupRow(row)) {
-          // unselect all children if the parent row is unselected
+          // select all children if the parent row is selected
           for (const cr of row.childRows) {
             newRawSelectedRows.add(rawRowKeyGetter(cr));
           }
@@ -323,7 +323,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
       const parentRowAndIndex = getParentRowAndIndex(row);
       if (parentRowAndIndex !== undefined) {
         event.preventGridDefault();
-        setActivePosition({ idx, rowIdx: parentRowAndIndex[1] });
+        setActivePosition({ idx, rowIdx: parentRowAndIndex[1] }, { shouldFocus: true });
       }
     }
   }
diff --git a/test/browser/TreeDataGrid.test.tsx b/test/browser/TreeDataGrid.test.tsx
index 8c825013a9..e8be78a270 100644
--- a/test/browser/TreeDataGrid.test.tsx
+++ b/test/browser/TreeDataGrid.test.tsx
@@ -397,6 +397,7 @@ test('cell navigation in a treegrid', async () => {
   await expect.element(rows.nth(1)).not.toHaveClass(rowActiveClassname);
   await userEvent.keyboard('{arrowleft}{arrowleft}');
   await expect.element(rows.nth(1)).toHaveClass(rowActiveClassname);
+  await expect.element(rows.nth(1)).toHaveFocus();
 
   await userEvent.keyboard('{end}');
   await expect.element(rows.nth(5)).toHaveClass(rowActiveClassname);