<Typography>
  {lastSelectedItem == null
    ? 'No item selection recorded'
    : `Last selected item: ${lastSelectedItem}`}
</Typography>
<Box sx={{ minHeight: 352, minWidth: 300 }}>
  <RichTreeView
    items={MUI_X_PRODUCTS}
    onItemSelectionToggle={handleItemSelectionToggle}
  />
</Box>