Sort seems to be rather a blunt instrument.
Sort a matrix with grouped rows and sums within the groups and Q will sort all the rows including the summed rows. I can’t quickly think of a situation where this is useful.
What would be more useful is if sort would sort within each group and leave the summed rows alone. After all, the sum within a group is the same, regardless of the order of the rows within the group.
Perhaps there’s a way to control sort behaviour but I’m not finding it.
If it isn’t available please consider adding this functionality.
Same goes for filter functionlity. Although, I’m not sure whether the sum should change as items are eliminated by a filter.