anchor.diff:          | Right sdlDeps ->
               match attemptMakeWorld plugin sdlDeps with
               | Right world ->
  +                RefWorld := world
  +                WorldChangers.Clear ()
                   let _ = run3 tautology targetDir sdlDeps form world
                   Constants.Engine.SuccessExitCode
               | Left error -> failwith error
  
positive.code: 
      /// Run Gaia from the F# repl.
      let runFromRepl runWhile targetDir sdlDeps form world =
          run3 runWhile targetDir sdlDeps form world
  
      /// Run Gaia in isolation.
  
negative.code:             | _ -> World.choose world
  
      let private run3 runWhile targetDir sdlDeps (form : GaiaForm) world =
          let world = attachToWorld targetDir form world
          populateCreateComboBox form world
          populateTreeViewLayers form world
  