‘Items on unallocated’ warning
Every Openbox model has a sheet called “Unallocated” on the far left of the main window. This is where new calculations go, and is a handy place to keep calculations that you are not yet sure where to put in the model.
But it is designed to be a temporary thing, used when drafting the model. In a finished model, every calculation should be in its right place and “Unallocated” should be empty.
One way to think of it is as a “to do” or “to do later” list.
Openbox will warn you (unless you ask it not to) if there’s anything in the unallocated list when you validate or build.