Here's a bonus question: Thanks to your tip, I can invoke a User Defined
Function to populate a cell!
What I'd really love to do additionally is invoke a User Defined function as
part of formula based custom Data Validation - when I try this on a UDF that
works great as a formula cell value, I get a "can't find named range"
error - i.e. the Data Validation dialog is not understanding that the name
of my function is a user defined function - I can enter built-in function
names, or named cells, but (so far) I can't enter a user defined function
Thanks again