Did some refactoring to simplify using SuperModel and registering models and collections.

app/collections/CocoCollection.coffee

@@ -5,4 +5,7 @@ module.exports = class CocoCollection extends Backbone.Collection
     super()
     @once 'sync', =>
       @loaded = true
-      model.loaded = true for model in @models
+      model.loaded = true for model in @models
+
+  getURL: ->
+    return if _.isString @url then @url else @url()

app/models/CocoModel.coffee

@@ -228,4 +228,12 @@ class CocoModel extends Backbone.Model
     model.url = makeUrlFunc(link)
     return model
     
+  setURL: (url) ->
+    makeURLFunc = (u) -> -> u
+    @url = makeURLFunc(url)
+    @
+    
+  getURL: ->
+    return if _.isString @url then @url else @url()
+    
 module.exports = CocoModel

app/models/SuperModel.coffee

@@ -8,6 +8,51 @@ module.exports = class SuperModel extends Backbone.Model
 
     @models = {}
     @collections = {}
+    
+  # Since the supermodel has undergone some changes into being a loader and a cache interface,
+  # it's a bit wonky to use. The next couple functions are meant to cover the majority of
+  # use cases across the site. If they are used, the view will automatically handle errors,
+  # retries, progress, and filling the cache. Note that the resource it passes back will not
+  # necessarily have the same model or collection that was passed in, if it was fetched from
+  # the cache.
+    
+  loadModel: (model, name, fetchOptions, value=1) ->
+    cachedModel = @getModelByURL(model.getURL())
+    if cachedModel
+      console.debug 'Model cache hit', cachedModel.getURL(), 'already loaded', cachedModel.loaded
+      if cachedModel.loaded
+        res = @addModelResource(cachedModel, name, fetchOptions, 0)
+        res.markLoaded()
+        return res
+      else
+        res = @addModelResource(cachedModel, name, fetchOptions, value)
+        res.markLoading()
+        return res
+    
+    else
+      @registerModel(model)
+      console.debug 'Registering model', model.getURL()
+      return @addModelResource(model, name, fetchOptions, value).load()
+      
+  loadCollection: (collection, name, fetchOptions, value=1) ->
+    url = collection.getURL()
+    if cachedCollection = @collections[url]
+      console.debug 'Collection cache hit', url, 'already loaded', cachedModel.loaded
+      if cachedModel.loaded
+        res = @addModelResource(cachedCollection, name, fetchOptions, 0)
+        res.markLoaded()
+        return res
+      else
+        res = @addModelResource(cachedCollection, name, fetchOptions, value)
+        res.markLoading()
+        return res
+        
+    else
+      @addCollection collection
+      @listenToOnce collection, 'sync', (c) ->
+        console.debug 'Registering collection', url
+        @registerCollection c
+      return @addModelResource(collection, name, fetchOptions, value).load()
 
   # replace or overwrite
   shouldSaveBackups: (model) -> false
@@ -17,7 +62,7 @@ module.exports = class SuperModel extends Backbone.Model
   getModel: (ModelClass_or_url, id) ->
     return @getModelByURL(ModelClass_or_url) if _.isString(ModelClass_or_url)
     m = new ModelClass_or_url(_id: id)
-    return @getModelByURL(m.url())
+    return @getModelByURL(m.getURL())
 
   getModelByURL: (modelURL) ->
     modelURL = modelURL() if _.isFunction(modelURL)
@@ -35,35 +80,33 @@ module.exports = class SuperModel extends Backbone.Model
     return _.values @models
 
   registerModel: (model) ->
-    url = model.url
-    url = model.url() if _.isFunction(model.url)
-    @models[url] = model
+    @models[model.getURL()] = model
 
   getCollection: (collection) ->
-    url = collection.url
-    url = url() if _.isFunction(url)
-    return @collections[url] or collection
+    return @collections[collection.getURL()] or collection
 
   addCollection: (collection) ->
-    url = collection.url
-    url = url() if _.isFunction(url)
-    if @collections[url]?
+    # TODO: remove, instead just use registerCollection?
+    url = collection.getURL()
+    if @collections[url]? and @collections[url] isnt collection
       return console.warn "Tried to add Collection '#{url}' to SuperModel when we already had it."
-    @collections[url] = collection
+    @registerCollection(collection)
 
+  registerCollection: (collection) ->
+    @collections[collection.getURL()] = collection
     # consolidate models
     for model, i in collection.models
-      cachedModel = @getModelByURL(model.url())
+      cachedModel = @getModelByURL(model.getURL())
       if cachedModel
         collection.models[i] = cachedModel
       else
         @registerModel(model)
     collection
     
-  # New, loading tracking stuff
+  # Tracking resources being loaded for this supermodel
 
   finished: ->
-    return @progress is 1.0 or Object.keys(@resources).length is 0
+    return @progress is 1.0 or not @denom
 
   addModelResource: (modelOrCollection, name, fetchOptions, value=1) ->
     modelOrCollection.saveBackups = @shouldSaveBackups(modelOrCollection)
@@ -108,8 +151,9 @@ module.exports = class SuperModel extends Backbone.Model
     # Because this is _.defer'd, this might end up getting called after 
     # a bunch of things load all at once.
     # So make sure we only emit events if @progress has changed.
-    return if @progress is @num / @denom
-    @progress = @num / @denom
+    newProg = if @denom then @num / @denom else 1
+    return if @progress is newProg
+    @progress = newProg
     @trigger('update-progress', @progress)
     @trigger('loaded-all') if @finished()
 

app/views/editor/level/edit.coffee

@@ -41,7 +41,7 @@ module.exports = class EditorLevelView extends View
     @levelLoader = new LevelLoader supermodel: @supermodel, levelID: @levelID, headless: true
     @level = @levelLoader.level
     @files = new DocumentFiles(@levelLoader.level)
-    @supermodel.addModelResource(@files, 'file_names').load()
+    @supermodel.loadCollection(@files, 'file_names')
 
   showLoading: ($el) ->
     $el ?= @$el.find('.outer-content')

app/views/editor/level/systems_tab_view.coffee

@@ -11,7 +11,6 @@ module.exports = class SystemsTabView extends View
   id: "editor-level-systems-tab-view"
   template: template
   className: 'tab-pane'
-  startsLoading: true
 
   subscriptions:
     'level-system-added': 'onLevelSystemAdded'
@@ -27,36 +26,23 @@ module.exports = class SystemsTabView extends View
 
   constructor: (options) ->
     super options
-    @toLoad = 0
     for system in @buildDefaultSystems()
       url = "/db/level.system/#{system.original}/version/#{system.majorVersion}"
-      ls = new LevelSystem()
-      ls.saveBackups = true
-      do (url) -> ls.url = -> url
-      continue if @supermodel.getModelByURL ls.url
-      lsRes = @supermodel.addModelResource(ls, 'level_system_' + system.original)
-      lsRes.load()
-      @listenToOnce(lsRes, 'loaded', @onSystemLoaded)
-      ++@toLoad
-    @onDefaultSystemsLoaded() unless @toLoad
-
-  onSystemLoaded: (lsRes) ->
-    ls = lsRes.model
-    @supermodel.registerModel(ls)
-    --@toLoad
-    @onDefaultSystemsLoaded() unless @toLoad
-
-  onDefaultSystemsLoaded: ->
-    @startsLoading = false
-    @render()  # do it again but without the loading screen
-    @onLevelLoaded level: @level if @level
+      ls = new LevelSystem().setURL(url)
+      @supermodel.loadModel(ls, 'system')
 
+  afterRender: ->
+    @buildSystemsTreema()
+    
   onLoaded: ->
+    super()
+      
   onLevelLoaded: (e) ->
     @level = e.level
     @buildSystemsTreema()
 
   buildSystemsTreema: ->
+    return unless @level and @supermodel.finished()
     systems = $.extend(true, [], @level.get('systems') ? [])
     unless systems.length
       systems = @buildDefaultSystems()