When rows are grouped, the rows per page are applied to groups and not to the actual rows in the table.

[TatyanaVl]

When rows are grouped, the rows per page are applied to groups and not to the actual rows in the table.

Lets say you have 1k, you can change the number of rows to 10 and you will see only 10 rows.
However if you add grouping and there are only 4 groups for the 1K rows, all 1k rows will be rendered and there is no way to change that because the number of pages refers to the groups

Ideally we want the number of rows per page be applied to rows.