Xander,
OK, it's clear now. I understand that Fusion prefers you work in a single file, and is written accordingly.
For kicks, I designed and saved a separate part (part 2) and inserted it into my part file (part-1). It shows up as a component, and includes the little chain symbol telling me it has external design inputs. Still, that's fine. However, I found that I'm not able to edit anything about part2 while working with part1. I have to open part2 to make any changes. In Solidworks I can "edit part" from within the assembly. It seems in Fusion you can only do this if the component was created as part of the main part - this is kind of a big deal for me.
I'm getting the impression that Fusion might be best suited for smaller projects with fewer parts, that are more stand alone than I'm used to. I design automation equipment, and there are many common parts that we share among machines (more than simple fasteners & etc). Often, we pull similar parts in and "save as" and then work from there - it saves lots of time to take something already existing and modify vs start from scratch. I was hoping that in those cases I could simply insert parts as components into my Fusion model, but not being able to edit them from within the assembly makes that more difficult.
Thanks,
Walt