I ran my first 'live' Roll20 game last night and this situation came up:
There were 30 tokens on the map in a relatively small space. As an opponent was killed, I would mark the dead token with the red 'X' and then change it to the Map Layer so that we could avoid picking up the wrong token and so that active tokens could stand in the same square over the corpse of the dead token.
Now, the token's states, bars, and nameplate does not appear once the token is changed to the Map Layer. I had a 'duh' moment where I kept trying to select a dead token on the Map Layer because it looked just like an active token on the Token/Object Layer. After a minute or two of' WTF?' and I realized that the token was actually a dead token on the Map Layer.
It would be helpful if a token's states, bars, auras, and nameplate were to remain visible (if allowed by the GM) no matter which layer the token resides on. Hope that all made sense. :)