> But we are taking on a little technical debt here, and it should probably be fixed before the next release.

I agree. But I'd rather like to deal with that particular technical dept by making the blackoil simulator always handle three phases. (i.e., removing the concept of "active" phases entirely as IMO it makes the code quite a bit more complicated than necessary and is prone to bugs.) For cases which only use two or a single phase from the outset, a separate simulator binary should be used. What do you think?