Undo Bug when undoing insert automation items

[ausbaxter]

Hello everyone, long time lurker here, I've made a quick script to add pooled automation to a group of selected items on a single track, unfortunately I cannot get the undo to function properly. After undoing, multiple envelopes will become visible for apparently no reason. I am not affecting envelope visibility in the script so i'm not sure what gives.

Anyone come across this before?



And here's the script:

num_selItems = reaper.CountSelectedMediaItems(0)
affectedTrack = reaper.GetLastTouchedTrack()
selMediaItems = {}
selEnvelope = reaper.GetSelectedTrackEnvelope(0)

function GetMediaItems()

  for i = 0, num_selItems - 1 do
  
    this_MediaItem = reaper.GetSelectedMediaItem(0, i)
    
    if reaper.GetMediaItemTrack(this_MediaItem) == affectedTrack then
    
      this_MediaItem_Start = reaper.GetMediaItemInfo_Value(this_MediaItem, "D_POSITION")
      this_MediaItem_Length = reaper.GetMediaItemInfo_Value(this_MediaItem, "D_LENGTH")
      
      table.insert(selMediaItems, {this_MediaItem, this_MediaItem_Start, this_MediaItem_Length})      
      
    end
  end
  
  table.sort(selMediaItems, function(a,b) return a[3] < b[3] end)
  
end

function CreateAutomationItems()
  
  for i, item in ipairs(selMediaItems) do
  
    if i == 1 then

      ref_length = item[3]
      
      auto_Item = reaper.InsertAutomationItem(selEnvelope, -1, item[2], item[3])
      
      pool_ID = reaper.GetSetAutomationItemInfo(selEnvelope, auto_Item, "D_POOL_ID", 0, false)
      
    else
    
      local pbkRate = ref_length / item[3]
      
      auto_Item = reaper.InsertAutomationItem(selEnvelope, pool_ID, item[2], item[3]* pbkRate)
      
      reaper.GetSetAutomationItemInfo(selEnvelope, auto_Item, "D_PLAYRATE", pbkRate, true)
      
      reaper.GetSetAutomationItemInfo(selEnvelope, auto_Item, "D_LENGTH", item[3], true)
      
    end
    
    
  end
end

function Main()

  reaper.Undo_BeginBlock()
  reaper.PreventUIRefresh(1)
  
  if selEnvelope ~= nil then
  
    GetMediaItems()
    CreateAutomationItems()
    
    reaper.UpdateArrange()
    
    reaper.Undo_EndBlock("Insert Unpooled Automation Items Under Selected Items On Selected Envelope", -1)
  
  else
  
    reaper.ReaScriptError("Error: Please select an envelope to create automation items on")
  
  end
end

Main()

Thanks for any insight!