Added watchers to list of properties to skip in deltas/patches.

app/lib/deltas.coffee

@@ -170,8 +170,8 @@ module.exports.pruneExpandedDeltasFromDelta = (delta, expandedDeltas) ->
 
 prunePath = (delta, path) ->
   if path.length is 1
-    delete delta[path]
+    delete delta[path] unless delta[path] is undefined
   else
-    prunePath delta[path[0]], path.slice(1)
+    prunePath delta[path[0]], path.slice(1) unless delta[path[0]] is undefined
     keys = (k for k in _.keys(delta[path[0]]) when k isnt '_t')
     delete delta[path[0]] if keys.length is 0

app/views/editor/level/save_view.coffee

@@ -4,6 +4,7 @@ forms = require 'lib/forms'
 LevelComponent = require 'models/LevelComponent'
 LevelSystem = require 'models/LevelSystem'
 DeltaView = require 'views/editor/delta'
+PatchModal = require 'views/editor/patch_modal'
 
 module.exports = class LevelSaveView extends SaveVersionModal
   template: template
@@ -39,7 +40,7 @@ module.exports = class LevelSaveView extends SaveVersionModal
     for changeEl, i in changeEls
       model = models[i]
       try
-        deltaView = new DeltaView({model: model})
+        deltaView = new DeltaView({model: model, skipPaths: PatchModal.DOC_SKIP_PATHS})
         @insertSubView(deltaView, $(changeEl))
       catch e
         console.error 'Couldn\'t create delta view:', e

app/views/editor/patch_modal.coffee

@@ -8,7 +8,9 @@ module.exports = class PatchModal extends ModalView
   template: template
   plain: true
   modalWidthPercent: 60
-  @DOC_SKIP_PATHS = ['_id','version', 'commitMessage', 'parent', 'created', 'slug', 'index', '__v', 'patches', 'creator', 'js']
+  @DOC_SKIP_PATHS = [
+    '_id','version', 'commitMessage', 'parent', 'created', 
+    'slug', 'index', '__v', 'patches', 'creator', 'js', 'watchers']
 
   events:
     'click #withdraw-button': 'withdrawPatch'