I think it's a bug, anyway.
In an assembly, I select a component (for example, Nut Runner - Vision Mount v3 in the image below).
The component highlights in the Feature Manager Tree. All is well.
However, I now want to mess with the Mates in this component, so I click the little arrow thing to expand my component.
Suddenly, my component has expanded in the FMT, but the highlight has moved to whatever happens to be the top item in the Tree View. In the example shown, it happens to be a folder entitled Camera and Projector, but it is whatever happens to be top in that view.
Surely, my highlight should stay on the component I just expanded, not move to some other, random component?
That's why I think it must be a bug. Unless you know otherwise...
A) It is a bug
B) It has not been fixed between 2016 SP5 and 2018 SP0.1, I will report it to my VAR.
Windows 10 Pro 64 Bit