I see that others would like the management of which tracks are visible in the PRV view improved.
I've got a few suggestions:
promote viewing a track in the PRV to a button in the Track view. Currently you need to right click on a clip, select view, select PRV. If I have multiple tracks selected then control-PRV would put the selected tracks in a PRV window
Someone else suggested multiple PRV views in the Multidock. This is a great idea.
In PRV promote track selection to a sub view that is always visible. Use the entire height of the screen so scrolling is not needed.
In PRV be able to filter so that only MIDI tracks are in the list (I'm just seconding this suggestion)
Corrected all occurrences of PVR to PRV for clarity. K