I was bitching about this a few weeks ago. Practically all the other teams that use ticketmaster systems already had this feature, but the Padres didn't.
The padres system was just a mess in general with not opening blocks of tickets fast enough. The opening blocks of tickets may still be a problem, but at least it's more visual now.
It's a great little tool as you can see the instances where row 4 is really the first row in a section. It's also good for grabbing isle seats. In addition it can give you an idea of how fast tickets are selling if you are on the fence on whether to buy or price shopping with stubhub.
Eventually all MLB teams will be using a tickets.com system (as tickets.com is owned by MLB Advanced Media). I don't think it has a similar feature unfortunately.
As nice as this feature is, it still doesn't excuse ticketmaster from charging the "convenience charge" per ticket instead of per order. By the way, they should rename it to the "inconvenience charge". They already charged a processing fee, why do they need another fee on top of that?