Problems with Crystal Report' s Details Session .

Question

Hallo,
In my billing program I created one report with Crystal report (Visual Studio 2008).

In a Detail Session there is a problem:

the Detail's height is >=221 always, also when there is only one  row in the bill.

I tried to reduce this space but there is impossible.

The printer prints into paper roll and the paper is large 7 cm.

Is There  mode to remove the blank rows ?

Thanks
I'sorry my english.