Show saved status of column preferences

app/assets/javascripts/admin/dropdown/controllers/columns_dropdown_controller.js.coffee

@@ -2,3 +2,4 @@ angular.module("admin.dropdown").controller "ColumnsDropdownCtrl", ($scope, Colu
   $scope.columns = Columns.columns
   $scope.toggle = Columns.toggleColumn
   $scope.saveColumnPreferences = Columns.savePreferences
+  $scope.saved = Columns.preferencesSaved

app/assets/javascripts/admin/index_utils/services/columns.js.coffee

@@ -1,13 +1,14 @@
 angular.module("admin.indexUtils").factory 'Columns', ($rootScope, $http, columns) ->
   new class Columns
+    savedColumns: {}
     columns: {}
     visibleCount: 0
-    saving: false
 
     constructor: ->
       @columns = {}
       for column in columns
         @columns[column.column_name] = column
+        @savedColumns[column.column_name] = angular.copy(column)
       @calculateVisibleCount()
 
     toggleColumn: (column) =>
@@ -18,10 +19,16 @@ angular.module("admin.indexUtils").factory 'Columns', ($rootScope, $http, column
       @visibleCount = (column for name, column of @columns when column.visible).length
       $rootScope.$broadcast "columnCount:changed", @visibleCount
 
-    savePreferences: (action_name) ->
+    preferencesSaved: =>
+      angular.equals(@columns, @savedColumns)
+
+    savePreferences: (action_name) =>
       $http
         method: "PUT"
         url: "/admin/column_preferences/bulk_update"
         data:
           action_name: action_name
           column_preferences: (preference for column_name, preference of @columns)
+      .success (data) =>
+        for column in data
+          @savedColumns[column.column_name] = column

app/assets/javascripts/templates/admin/columns_dropdown.html.haml

@@ -7,4 +7,4 @@
       %span.name {{column.name }}
     %hr
     %div.menu_item.text-center
-      %input.fullwidth.red{ type: "button", value: 'Save As Default', ng: { click: "saveColumnPreferences(action)"} }
+      %input.fullwidth.red{ type: "button", ng: { value: "saved() ? 'Saved': 'Save As Default'", disabled: "saved()", click: "saveColumnPreferences(action)"} }