Can't extend wall layers vertically

[jwilhelm]

The tutorial on modifying wall layers in section indicates that if you select the top or bottom shape handle & unlock it that you can extend a wall layer above or below the rest.
I have unlocked all adjacent layers as indicated but I cannot drag the layer down. It also says that when you seclect the shape handle, two new instance variables become available, I dont see them either. In this case I have a stud wall furring next to a concrete wall, I want to extend the concrete wall below to the footing. what am I doing wrong?

[Allen Lacy]

One possibility is that If you have attached the wall to something (roof, ceiling, floor, etc), then extend layers will not work.