I'm looking for a way to include a drop-down field in a form that
automatically sorts the source values ascending. Sorting the source data is
not a possibility.

I'm using Excel 2003. I have a 'master' worksheet that pulls customer data
from numerous separate data entry Excel files via links. I have a 'customer
summary' worksheet in the same workbook as the master worksheet is in. The
'customer summary' worksheet pulls information for a specific customer from
the 'master' worksheet into a single-customer view.

Currently, I'm using data validation in the 'customer summary' sheet to
select a customer. The drop-down isn't sorted alpha so it's difficult to
find a specific customer. Then, I use VLOOKUP to pull over the data for that
customer into the 'customer summary' sheet.

In addition to data validation, I tried a combo box but couldn't get that to
sort alphabetically either.

Any thoughts / solutions would be greatly appreciated!

FYI - If your solution is to do something via code, please provide a lot of
detail / instruction.