Thanks Chip

I was afraid it is something like ...

c you should remember than VBA code, whether called directly or
indirectly
c from a worksheet cell, cannot change anything. It can only return a
value.

The setHighlight() returns a nice string saying "done". The required
effect is to _change_ the reference.

Is there some way to affect changes from inside a function? Say launch
another macro or something?

Thanks for pointing me out of a dead-end.

Cheers,
Will.