Hey GT, Ron and I figured out the how - and you can do a category. The issue is for some reason you can't be successful if you click on the global check box to select all the products (as one would hope) It fails to "apply" the selections to the coupon.
The resolve is to click each one individually and then it works. Again this is 1.1.9
Unfortunately, in 1.2.0 and 1.2.1 one only can choose a product by starting with the BEGINNING of a product name - there isn't any way to select a category. It would be nice to get more functionality back with the coupon codes. Seems we've regressed in this, hopefully they will improve it for future versions.
Lee