... to its twisted position, its nominal position along the centre-line of the track does not change. The amount of crab movement appears in a separate box, and the centre dimension does not change. If you first twist a timber and then try the crab and along (forward/backward) functions on it, you will see the difference between them. Here's a timber which has been twisted and then crabbed without moving it along -- you can see that it wouldn't be meaningful to change its centre dimension showing: 2_251828_440000000.png If a timber has not been twisted there is no reason to crab it -- use the along mouse action or the forward/backward buttons instead. If you play with all the timber-shoving functions you will soon see how they work. I am in the process of moving timbers (for the first time) and note that when they are moved the outline of the timber in its original position remains, is it possible to remove this "ghost"? This must mean that you have stored a background template ...