I have a really strange problem that just has me baffled. I have a
spreadsheet set up that pulls out unique items from a list. It works really
well. Here is the setup:

Cell F4:
=OFFSET($D$3,MIN(IF(COUNTIF($F$2:F3,D3:$D$201)=0,( ROW(D3:$D$201)-ROW($D$3)))
),0)
This formula is then copied down to F30.
Cells D4 to D30 have various names, some of which are duplicates.
Cell D3 has an apostrophe (cell appears blank).
Let's say there are 12 unique names in the list. Cells F4 to F15 then lists
all of them, once each.
Cell F16 has a zero.
Cells F16 to F30 are blank (this is the reason for the apostrophe in cell
D3).
So it works great. I get my unique list, a zero to signify the end of the
list, and blanks after that.

Here's the problem. If I do any editing of the formulas in the F-column,
the process no longer works correctly. This prevents me from extending the
range of my D-column. If I just copy the existing formula further down, it
still works. One thing that seems to do the trick is making the formulas
array formulas. However, this GREATLY increases the calculation time. And
the formulas that work before editing are NOT array formulas. Any help
would be appreciated.

Ken