I am OK with having the drum map on top of the window, and the velocities on the bottom of the window, but whenever I touch a drum-note, the piano-thingy-whatever-it-is automatically pops open in the middle of the screen.  I then have to close it.  I don't want it popping up, and don't see what purpose it is performing in any case.  How to kill it?
 
PS: Whose idea was this at Cakewalk?

This is a known problem with multiple tracks in the PRV. It also happens with non-Drum Map tracks - the Controller Panes can re-pop up when you click on a note from a different track than the one currently selected. It's like, SONAR wants to re-position the Controller/Note panes back to default (or whatever) when you change tracks.
 
It *almost* makes sense but in practice it's really annoying. Feel free to submit a Problem Report on this. The more noise the issue gets, the more likely it will be addressed in a future update.

Agreed that this doesn't make practical sense.  It may make sense from a coding point of view, but this interrupts the workflow.