sketch entities

Since I can't select a sketch area to create a surface, must pick sketch entities... (I haven't tried "click and drag" a window yet)...I want to "Chain-Select" the curves. OK... dragging a window did work. I had only the sketch I wanted displayed...

I was almost certain that Onshape already had the capability to report the combined length of a chain of sketch entities (eg lines, arcs - not sure if it extended to chains including splines) once they were selected. In my recollection the readout at bottom right showed the aggregated length. I can't get that to work for…