Was there a chance in the last update to disallow multiple instances?

[Duggan]

I used to keep a few HeroLab instances open, particularly when moving characters around, or comparing systems. I could invoke them by invoking Hero Lab another time, either directly or through invoking a portfolio file. Recently, I tried to do so, and nothing happens. Was something changed? Is there a way to restore the former functionality?

I don't think I changed any settings recently, but it's possible I did so accidentally.