title: Kendo Grid: add new row with nested object stopped working
body: <p>I'm filling a Kendo data grid from nested JSON by this way:</p>
  
  <p><a href="https://stackoverflow.com/a/24441318/535556">https://stackoverflow.com/a/24441318/535556</a></p>
  
  <p>Everything works fine until I click on the "Add new row" button. </p>
  
  <p>Then I receive a console error message:</p>
  
  <p><em>"Uncaught TypeError: Cannot read property 'street' of undefined "</em></p>
  
  <p>I would like to ask how to format the data properly to obtain nested JSON object with updated data?</p>
  
  <p><strong>Many thanks for any advice.</strong></p>