Tim - as everyone knows, I take particular interest in Jackson ( including his throw-ins. )..... It was good to see a successful one - leading to Lee's 2nd goal.
I too have noticed his feet 'encroaching' into the pitch ( in front of the line). I have wondered if his throws could be deemed a 'foul throw .' However the laws governing throw-ins merely stipulates that only a 'part' of the feet need to be on or behind the line at the point of release of the ball. I have seen Jackson 'stretching ' this point.
I am not surprised that any 'foot fault' is not punished. Every time a player takes the throw, the linesman never watches that player -- the linesman always seems to be more interested in any 'engagement' between the players likely to receive the ball - or ( more ridiculously ), seemingly looking for players who might be 'offside.' ----- and regularly fail to see the strangleholds and shirt pulling.
I am unsure if the throw-in law ( relating to the position of at least part of the feet being on the line ), has changed in its' interpretation -- just like the ridiculous nonsense of the ball being placed outside the corner quadrant when corners are taken --- and yet deemed legal because only a part of the ball has to 'hover above' the quadrant !
It doesn't really help the players or the fans when the FA make it up as they go along ---- The goal that Man City scored last week ( v Aston Villa ), that caused controversy - because of the City player coming from 'offside' - behind the Villa defender, and robbing the ball leading to the goal --- was justified by the Referees Association - because the defender had 'intentionally' played the ball - before he had it nicked off him....... A couple of days later the Referees Association tell us that the same situation will not be allowed in future ----- well, not again until there's R in the month !