<Stack direction="row" spacing={2}>
  <Button onClick={handleInvertItems}>Invert first tree</Button>
  <Button onClick={handleUpdateItemOnTop}>Update item on top</Button>
</Stack>
<Typography>Item on top: {itemOnTop}</Typography>
<Box sx={{ minHeight: 352, minWidth: 300 }}>
  <RichTreeView apiRef={apiRef} items={items} />
</Box>