The standard feature does not provide a feature to change or add the location of the scroll bar in the subgrid.

Since there is no scroll bar that can be moved vertically, the header moves and it is very difficult to use.

Also, the scroll bar for horizontal movement is very difficult to use because it cannot be moved horizontally unless it is scrolled to the bottom.

Therefore, if you can customize the scrollbar in the subgrid, I think it will be a very convenient feature that will make it easier for users to use.

So I hope that the ability to customize the scroll bars in the subgrid will be implemented.