This seems to work, but has some overhead involved:

Place this in the ThisWorkbook area
Private Sub Workbook_SheetCalculate(ByVal Sh As Object)
msgbox("This will capture your activity")
End Sub

And
add a formula like this that will span an entire column of your filtered
table:

=SUBTOTAL(102,E4:E21)
where E4:E21 will span your entire filtered table.  If Calculate is set to
automatic, the formula will trip the sub above and you can do whatever.  I
could find no "direct" way to capture a filter event.  HTH.

Mike - thanks - very logical and obvious when its pointed out to you. This
will obviously work with calc set to auto - I am set to manual to increase
speed (lots of calcs) - I will need to think it through and may have to
compromise the man/auto or scrap what I was trying to do - in any event,
thanks for the help