Fix bug.

app/models/file_manager_setting.rb

@@ -231,6 +231,9 @@ class FileManagerSetting
     self.modules_saved_info = models_dict
     self.modules_keys = modules_info.keys
     self.save
+    if self.class.all.count > 1
+      self.class.where(:id.ne=> self.id).destroy
+    end
     modules_info.each do |module_key, uploaders|
       # module_app = ModuleApp.where(:key=> module_key).first
       # I18n.t("module_name.#{module_key}")