When using the grid I always leave at least one empty row at the bottom, making it easy to fill in extra data.
But when clicking on a column header and getting the grid sorted, then the empty row gets sorted as well which isn't surprising of course. But not necessarily always what you want to be happening.
So may I suggest a future sorting option to be added, like 'ignoreEmpyRows'.... and maybe implemented in a way which moves ALL empty rows to the bottom upon sorting, no matter which way the sorting order is.