private void _addRight(object obj)
 {
     using (var selector = new SecurityObjectSelectorViewmodel(_authenticationService))
     {
         if (UiServices.ShowDialog <Views.SecurityObjectSelectorView>(selector) != true)
         {
             return;
         }
         var right = _engine.AddRightFor(selector.SelectedSecurityObject);
         if (right == null)
         {
             return;
         }
         var newRightVm = new EngineRightViewmodel(right);
         Rights.Add(newRightVm);
         SelectedRight           = newRightVm;
         SelectedRight.Modified += EventRightViewmodel_Modified;
         IsModified              = true;
     }
 }