Bristol_Jonesey
Go to Tracks > Pick Tracks in the PRV.
Select just ONE track.
Delete any spurious controller lanes.
Rinse & repeat.
I don't know how to say this any more plainly. There are no spurious controllers. They all serve a musical purpose.
But even if I did have some superfluous lanes, that should not put the UI into a catch-22 that makes it absolutely impossible to use.