Hmm I need to go back in and check this as when I was first trying it out last night it wasn't selecting brushes for me (although they were ones I had already put down before the update in case that matters ? )
*Edit
Just gone in and checked and it's acting a bit weird for me. At first I thought it just doesn't work on brushes laid before the update went live but then I tried it on a couple of other holes and it does.
Tested 5 holes in total, 4 built before the update and 1 after. Area Select picks up the brushes on 3 holes (incl the new one) but not on the other 2 ??
*Edit #2
Ok it does work on all the holes but on the ones built before the update it will only pick up the brushes if I expand the area large enough to cover the entire hole (and then it selects everything of course) whereas with the new hole built after the update I can just select smaller areas and it picks up the individual brushes within.