[bFooz]

I agree that this would be useful. I've been scripting a bit today to make track locking somehow available, but I have not find a reliable way. This is what I have:

-- USER VARIABLES ---------------------------------------------------

  --string which all lockable folders contain
  userFolderString = "BUS"
  
  --minimum height of folder tracks
  userHeight = 200 --px

-- END USER VARIABLES----------------------------------------------

function main()
  
  trackNum = reaper.CountTracks(0)
    
  for i=0, trackNum-1 do
  
        track = reaper.GetTrack(0, i)
        
        --get name
        name = ""
        _, name = reaper.GetSetMediaTrackInfo_String( track, "P_NAME", name, false )
        
                   
        --if the name contains desired string
        if name:find(userFolderString)~=nil then
            
               reaper.SetMediaTrackInfo_Value(track, "I_HEIGHTOVERRIDE", userHeight )
                                  
        end --if
        
  end --for i

  reaper.TrackList_AdjustWindows( false )
  reaper.defer(main)
end --function main

main()

The main problem is that when using a standard vertical zoom action, Reaper is taking the height of the last touched track as a basis. That means that when a locked BUS is a last touched track, the you cannot make the other tracks smaller that the BUS