The interface for the spreadsheet classes isn't too complicated, since it's a view-only interface -- the user doesn't actually change anything in the spreadsheets through the interface. Rather, three things need to be made visible:

1. Type of formula the spreadsheet is using
2. The values being used to calculate the net value
3. The net value as calculated by value method.

The key issues are:

• Dependency tracking.
• Creating the core SpreadSheetViewContainer.