As I said, different resetTypes do not change the behaviour. This report is a "little" complicated so some fields are filled from Java, this is the only solution I have found to avoid the same calculation running for every row (put the calculation in the field). But with that solution I have to calculate almost everything twice (for the field and for the summary) which is ugly. But as soon as I put the calculation into a variable it is evaluated every row, resetType does not change anything for me. My guess was, that a "first" on a group will only evaluate once in a group (which is sufficient and would be exactly what I need, but the first of the group is called for every row in the group).