Level Editor doesn't need to load your session or its hero config (or break doing so). Fixed adding unconfigured heroes to levels busting the level.

app/lib/LevelLoader.coffee

@@ -31,6 +31,7 @@ module.exports = class LevelLoader extends CocoClass
     @opponentSessionID = options.opponentSessionID
     @team = options.team
     @headless = options.headless
+    @sessionless = options.sessionless
     @spectateMode = options.spectateMode ? false
     @observing = options.observing
 
@@ -55,7 +56,7 @@ module.exports = class LevelLoader extends CocoClass
       @listenToOnce @level, 'sync', @onLevelLoaded
 
   onLevelLoaded: ->
-    @loadSession()
+    @loadSession() unless @sessionless
     @populateLevel()
 
   # Session Loading
@@ -260,8 +261,8 @@ module.exports = class LevelLoader extends CocoClass
   checkAllWorldNecessitiesRegisteredAndLoaded: ->
     return false unless _.filter(@worldNecessities).length is 0
     return false unless @thangNamesLoaded
-    return false if @sessionDependenciesRegistered and not @sessionDependenciesRegistered[@session.id]
-    return false if @sessionDependenciesRegistered and @opponentSession and not @sessionDependenciesRegistered[@opponentSession.id]
+    return false if @sessionDependenciesRegistered and not @sessionDependenciesRegistered[@session.id] and not @sessionless
+    return false if @sessionDependenciesRegistered and @opponentSession and not @sessionDependenciesRegistered[@opponentSession.id] and not @sessionless
     true
 
   onWorldNecessitiesLoaded: ->
@@ -322,7 +323,7 @@ module.exports = class LevelLoader extends CocoClass
     resource.markLoaded() if resource.spriteSheetKeys.length is 0
 
   denormalizeSession: ->
-    return if @headless or @sessionDenormalized or @spectateMode
+    return if @headless or @sessionDenormalized or @spectateMode or @sessionless
     patch =
       'levelName': @level.get('name')
       'levelID': @level.get('slug') or @level.id

app/views/editor/level/LevelEditView.coffee

@@ -58,7 +58,7 @@ module.exports = class LevelEditView extends RootView
     super options
     @supermodel.shouldSaveBackups = (model) ->
       model.constructor.className in ['Level', 'LevelComponent', 'LevelSystem', 'ThangType']
-    @levelLoader = new LevelLoader supermodel: @supermodel, levelID: @levelID, headless: true
+    @levelLoader = new LevelLoader supermodel: @supermodel, levelID: @levelID, headless: true, sessionless: true
     @level = @levelLoader.level
     @files = new DocumentFiles(@levelLoader.level)
     @supermodel.loadCollection(@files, 'file_names')

app/views/play/level/tome/TomeView.coffee

@@ -58,8 +58,7 @@ module.exports = class TomeView extends CocoView
   afterRender: ->
     super()
     @worker = @createWorker()
-    #programmableThangs = _.filter @options.thangs, (t) -> t.isProgrammable and t.spriteName isnt 'Hero Placeholder'
-    programmableThangs = _.filter @options.thangs, 'isProgrammable'
+    programmableThangs = _.filter @options.thangs, (t) -> t.isProgrammable and t.programmableMethods
     @createSpells programmableThangs, programmableThangs[0]?.world  # Do before spellList, thangList, and castButton
     @spellList = @insertSubView new SpellListView spells: @spells, supermodel: @supermodel, level: @options.level
     @castButton = @insertSubView new CastButtonView spells: @spells, level: @options.level, session: @options.session
@@ -73,7 +72,7 @@ module.exports = class TomeView extends CocoView
 
   onNewWorld: (e) ->
     thangs = _.filter e.world.thangs, 'inThangList'
-    programmableThangs = _.filter thangs, 'isProgrammable'
+    programmableThangs = _.filter thangs, (t) -> t.isProgrammable and t.programmableMethods
     @createSpells programmableThangs, e.world
     @spellList.adjustSpells @spells
 
@@ -112,7 +111,6 @@ module.exports = class TomeView extends CocoView
     for thang in programmableThangs
       continue if @thangSpells[thang.id]?
       @thangSpells[thang.id] = []
-      thang.programmableMethods ?= plan: {name: 'plan', source: '// Should fill in some default source.', permissions: {readwrite: ['humans']}}
       for methodName, method of thang.programmableMethods
         pathComponents = [thang.id, methodName]
         if method.cloneOf