There's a mouthful.
Anyway, here's the background:
I know that pulling criteria from different criteria sets in a single list can sometimes have unexpected effects for users. If you pull, say, "Performance Season" from one criteria set and "Price Type" from another, then generally you will get people who have bought tickets to that Season AND have, at some point (not necessarily in that Season), bought a ticket with the chosen Price Type. But if you pull "Performance Season" and "Price Type" from the same criteria set, then you will get people who bought a ticket with the chosen Price Type in the Season in question.
What I don't know is how it works on the back end. Is it based on the View the criteria are looking at (that is, all the selects for the same View get combined) or is it based on the Criteria Set (that is to say the Keyword Category)?
What I'm trying to decide is how to deal with a request to extend the criteria available within a Criteria Set: Should I add a new keyword definition using the same view (if possible) to a defined as local Keyword Category, or does it need to be the same Keyword Category? And in the latter case, is it okay to extend built-in Criteria Sets, or should I create a new one that has all of the definitions we need?
Love this question. It sounds like you got about to where I did, too, but then I just stopped and said to myself "oh well, I will figure this out later" but then never went back and did anything. Because training people in using List Manager is hard enough, trying to explain to them when two things are going to work with each other and when they are not is just an exercise in frustration. Anything that can make that easier gets my vote.