Data validation and application.volatile
 

I have created a couple of custom functions where I want my custom function
to calculate even though a cell it references has not been directly edited. I
use application.volatile to accomplish that, this also allows the function to
calculate prior to a worksheet change event, which is also something that I
want.

However, the application.volatile causes problems with other code I have;
specifically the code assigned to a button that references a cell where a
choice has been made using a data validation list. The code will not execute.
Any ideas as to what is causing this to happen? Or, is there a different way
to use application.volatile?

George