title: Clicking on the Delete button in navigator to delete offline data
body: <p>I just tried deleting a few selected rows by clicking on the Delete button in the navigator of a grid, but I got a warning message in the confirmation popup saying that the url is not set. I am wondering if the navigator supports deleting offline data without setting a url. </p>
  
  <p>Maybe I can override the default delete function?</p>
  
  <p>Thanks.</p>