I am wading thorough
MsgBox "You don't appear to have any words interesting enough to index!"
with
MsgBox "IndexActiveDocument- You don't appear to have any words interesting enough to index!"
That is, including the name of the procedure with every MsgBox (or my custom logging procedure) call.
I am motivated by an error report from a user who says "I got just an empty pop-up message box".
I don't know whether the MsgBox was mine or not, but from now on, I'll know if it WAS one of mine; also I'll get some idea of what the user might have been attempting.