Oh, OK. I take it that you'd prefer that I retained the previous "before/after" selection then? It would be relatively easy to do. What do others think?
I agree that it should retain the previous selection. The current set-up is, as
Paul1609 says, a bit of a chew when looking at longer journeys (which is presumable exactly what TS is most handy for) and when you ask it look departing than 13:00, it switches to looking for arrivals before 13:00. That could be a six or seven hour jump, and is either going to put folks off or just increase the number of searches required to get the requested results.
It may be a particular irritation because the algorithm is (understandably) set to look for 'cheap' first. That regularly means that a 'departing after 13:00' search returns a first option departing after 14:00, which may be too late. So the user is also understandably going to want to track back to see what else is available around about.
This is, of course, on a non-split basis, what the WebTis matrix is so efficient at showing.