Sort only non empty rows

Hi,

Is there a way to sort only the non empty rows (something equivelent to setSortColumn which operate on rows).

I have a grid which I always want it to be 20 rows. Most of the times only few rows are filled with actual data and the rest of the rows are empty.
When the user sort the grid it also take into account the empty rows.


Thanks,
Yaron

Is there any anwer to this problem?
Can some one help with this?