fix: Tree scrolling elements into view

The tree will now correctly scroll the active item into view when using
the left and right arrow keys to jump to the expandable parent with the
left arrow key or to the first child with the right arrow key.

packages/tree/src/useTreeMovement.ts

@@ -238,7 +238,12 @@ export default function useTreeMovement({
           if (!expandedIds.includes(itemId)) {
             onItemExpansion(itemId, true);
           } else {
-            setFocusedIndex(focusedIndex + 1);
+            const nextIndex = focusedIndex + 1;
+            const nextItem =
+              itemIdRefs[visibleItems[nextIndex]?.itemId]?.ref.current;
+
+            setFocusedIndex(nextIndex);
+            scrollIntoView(event.currentTarget, nextItem);
           }
           break;
         case "ArrowLeft":
@@ -248,7 +253,11 @@ export default function useTreeMovement({
             const parentIndex = visibleItems.findIndex(
               (item) => item.itemId === parentId
             );
+            const parentItem =
+              itemIdRefs[visibleItems[parentIndex]?.itemId]?.ref.current;
+
             setFocusedIndex(parentIndex);
+            scrollIntoView(event.currentTarget, parentItem);
           }
           break;
         case "a": {