Pflow has always had integration issues in max, but it apparently got worse in 2015. There's no longer a "select layer and objects" button in the Layer Manager for some reason, so now it seems to be utterly impossible to select those particle objects that don't show up otherwise.
To explain, I'm trying to animate the visibility of my particles (not the PF source or events, as that is also bugged...) and previously the only way to select them was to move all objects away from Layer 0 so it appears empty, then click "select objects", which selects the particles as they are still in the layer despite not showing up in the list. Now that doesn't work.
This also means it's now impossible to move particles between layers, leading to other problems.
I'll have to use a different solution for now, but I'm posting this just in case an employee happens to see it. PF objects need to be made visible in the max interface.