Scope Box and Plan Region

[Bluefairy]

What is the difference between scope box and Plan Region (under plan view)? There also seems to be a choice under properties:

Plan Region
- Plan Region 1
- Floor Plan : (first floor)

Scope Box
- Scope Boxes (1)
- Floor Plan : (first floor)

What does the above mean? Why would you use scope boxes (1) or floor plan:...