Grasping at straws now.

What it cannot be:
-Formulas are out. You couldn't enter a value without wiping the formula.
-Cell formatting doesn't really change the value input, it just makes it look different. Nor can the format of one cell impact the values of another.
-Conditional formatting can't change the value in a cell.

Was there a limit on the number of levels? 1.2.3.4.5.6...
Do you still have a version that works?
Dose it work if the zero's are taken out?

The more I think about it this sounds like an add-in macro of some kind. One that is automatically validating and rebuilding the column everytime the sheet is calculated. That kind of item could be very susceptable to breakage if a user gave it garbage input. Referring to the zeros of course. If that is the case taking the zeros out should restore the function.


Are there add-ins are installed in the workbook? What are they?

Btw: This is something I could use. For a WBS listing.