It's not quite that simple. you can list by "Changed" by clicking this title in the aircraft list, but then every time that aircraft is detected, the time will change so the list will change order.
I tend to sort by Mode C order, so that aircraft a "grouped" as most operators have blocks of Mode S codes allocated.
When I'm watching aircraft at Heathrow and listening to the radio, I sort by Flight ID as this makes it easy to find the aircraft I'm listening to.
If I'm only interested in a particular fleet or two, I put these in the Fleet Watch list so that I have a simplified list.