This was a Fan Fix for the Horizontal displacement that occured when a Macaroon(pre Cataclysm) bar with a 0-button-state switches state, if it's placed along left/right side of the screen or Snaped To left/right side of another bar.
Just some additional code and some minor changes to Mauls code in file Macaroon_Bars.lua:
local function updateBarSize(bar)
Install: replace your old Macaroon_Bars.lua file in your Macaroon folder with this one.
Updated to work with Macaroon:Autohide-show on ModKey
If you don't install that patch first you shouldn't install this update.