A quick question about the bergheil - what's the function of the little lever between the front standard posts? Does it lock the standard in place along the rails (I thought the pinchy bits took care of that) or lock shift? What position is locked and what position is unlocked? As indicated in my other thread on the bergheil, the rails are a bit gunky with hardened lubricant so I can't really tell if the lever is having any effect on the sliding of the standard (locking it down).