Thanks Andrew! Did not know that (or forgot).
Found it in the "Scan->Spread Book" after refining the selection to permit it to display.
It seems a better choice for this info would be when one is working an order, rather than hidden away like that. -- However, this is limited to the subset of orders within TDA!
It would be nicer to be able to see all orders.
I also submitted a request to TDA about it, so, perhaps more info will be forthcoming.