To add to the drum map suckyness.... here's another annoyance (not really a bug, but screws the UI big time)...
 
If I display two midi tracks with different drum maps under piano roll, when flipping between the tracks on the drum roll the scrollbars keep moving around, it does not remember the last position for the track... very annoying,... (Note I wouldn't expect both to be displayed at the same time because the notes are mapped differently).
 
I haven't tested with two MIDI tracks using exactly the same drum map under one piano roll (in that instance I would expect both drums maps to be displayed if visible).

I seem to have a workaround for this issue (I hope). As long as I use my key bindings to switch between views, without actually closing the piano roll view, I am able to switch to Track View, Console, etc., and then back to piano roll without having to resize the left column (where the names are displayed in the drum pane. The column stays exactly where I left it. Perhaps I'm too late to this party and you guys already know this, but I just found this thread and thought I'd chime in just in case.

pinguinotuerto
I seem to have a workaround for this issue (I hope). As long as I use my key bindings to switch between views, without actually closing the piano roll view, I am able to switch to Track View, Console, etc., and then back to piano roll without having to resize the left column (where the names are displayed in the drum pane. The column stays exactly where I left it. Perhaps I'm too late to this party and you guys already know this, but I just found this thread and thought I'd chime in just in case.

Another workaround is putting the PRV in the multidock.

Yes, I thought of mentioning that, but I thought it would be redundant, since once it opens it goes in the MD automatically (for me anyway), hence, toggling between views with either key bindings for launching views, or the Expand/Collapse multi-dock command, does the trick. Glad you mentioned it, though. I'm still getting the hang of X3 and am not sure if things are docked in the MD automatically or not once you open them regardless of which scene or view mode you're in.