Learned he could stand in his crib :(

ltate_8

DS has been pulling himself to standing at furniture now for about three weeks.  The crib has been at its lowest setting for over a month now.  Today he just figured out that he can also stand in his crib!  Naps and bedtime today were rough.  I am afraid he will pull himself out of the crib, so I keep looking in on him, which doesn't help!  How long did your LO's fight sleep when they learned this new trick?