It looks as though because so many controller lanes are exposed, Sonar cannot display the +/- buttons for each one.
 
Try shrinking the notes pane right down to a thin sliver, see if this helps

>> And most maddeningly, when I hide tracks, the controllers don't hide.
 
That's a great idea for a feature request.

John
 The above is from the help file.

Thank you for posting the generic help information.  Now, could I get you to look at my example that shows it is IMPOSSIBLE to do anything with that screen if there are more than a couple of controller lanes?
 
This is a fundamentally bad design that guarantees a catch-22 if a person happens to have more controller lanes than the UI designers saw fit to test.  This has always been bad.  Now it is impossible with the multiple tracks view.
 
In addition to only allocating screen space for lames associated with tracks in view, there ought to be an "auto-zoom" option that guarantees if you can click on ANYTHING in the controller lanes, SOMETHING will expand up to a minimally useful size.
 

stickman393
>> And most maddeningly, when I hide tracks, the controllers don't hide.
 
That's a great idea for a feature request.

Thanks.  I have done that at http://forum.cakewalk.com/FindPost/3166007

I can easily replicate your screenshot above.
Have you tried what I suggested and drag the divider between the controller and note panes upwards?
This should reveal enough of the controllers to enable you to access their +/- buttons
 

Another solution:
 
 
Go to Tracks > Pick Tracks in the PRV.
Select just ONE track.
Delete any spurious controller lanes.
Rinse & repeat.

John
 

The above is from the help file.
Below is a screen shot with a close up the lane controls. The minus sign will remove a lane.
 
 

John,
What I don't understand is, say you have 3 tracks you're working on. You only show track 1, and then hit all the minus signs on the tracks your not working on to make it less dense. What happens if I want to then hide track 1 and show track 2 to modify it. Do I then need to delete the controllers for track 1 and add controllers for track 2?
 
Walt
 

You can easily have separate PRv's for each Midi track, all docked in the Multidock, though you do lose the ability to edit in context with the other tracks.

Bristol_Jonesey
Have you tried what I suggested and drag the divider between the controller and note panes upwards?
This should reveal enough of the controllers to enable you to access their +/- buttons

Yes.  It comes nowhere close to exposing those buttons in this case.There are actually a few more controllers than I was aware of.  I think there are 5 controllers per channel -- total of 25.
 
This is a fundamentally bad UI design when it depends on buttons in a collapsible section being visible.  Always has been bad.  But it gets many times worse now that PRV can support multiple instruments.  I have identified several really simple solutions that should not be difficult to implement and would eliminate the inherent catch-22 nature of this UI design.  See http://forum.cakewalk.com/In-PRV-controller-lanes-are-practically-unusable-please-fix-this-m3166007.aspx#3166007
 

Bristol_Jonesey
You can easily have separate PRv's for each Midi track, all docked in the Multidock, though you do lose the ability to edit in context with the other tracks.

 
Well no.  This has always been a problem,  It is just worse in the case of multiple-track PRV.  If you have single track PRV with, say four controller lanes, on a medium-sized screen you will find this practically impossible to use.