Thanks, this worked!

"zvkmpw" wrote:

Here's one way, but it's different from the approaches you mentioned.

In the left-most column header, put
=IF(OFFSET(Sheet1!$A$1,COLUMN()-2,0)="","",
OFFSET(Sheet1!$A$1,COLUMN()-2,0))
but don't use 2; instead, use whatever number makes the OFFSET point
to <first_column_element. If <first_column_element isn't in Sheet1
column A, change those parts too.

Then select the cell containing the formula and drag rightward for the
maximum length the column can ever have. Because of the IF test, a
header cell should be simply empty if the corresponding column element
is absent.
.