Infact, there should be an auto-top-up feature... just last night my first 2 hands at one table where crazy, against the same op:

I had QQ and triped up, 4 to the straight was out by the river (which ofcourse he had...) so my stack went straight from $20 to 12.5

The very next hand im dealt AKs and flop a FH, he must of hit the flush which was out on the turn and we got all-in, so my stack was back up (tho now to $25) $5 over the buyin which is nice, but if I would of been able to top up after the previous hand I could of profited a hell of alot more