Hmm. I get the same result in Producer X3 and Producer X2: If I use a drum map, the piano roll empties out of notes and I only see the hits in the drum pane.
So now I am wondering if I am crazy for remembering it working at one point.
But clearly you do remember it working:
>> The map would live happily above the actual note pane and both were visible at the same time
So I'm guessing this was an earlier version of Platinum.
Just for fun I rolled back to 23.4 (April 2017 release) which is the earliest release I still have in my installs folder.
Oh goodness, 23.4 is the one with the magically zoomed-in PRV... Yeah, I don't see it working here either.
I'm not doing anything special, just creating a midi drum track that uses a drum map to talk to Addictive Drums, and then throwing up the PRV on the MIDI track and opening the pane splitter.
Having tested this, I'm going to go back to 23.8.