title: Custom UIPickerView
body: <p>I want to use custom picker view that will add a check sign in front of selected row.
  I have used apple sample code for custom UIPickerView on the UICatalog example. I was able to add the check sign for a given row when creating the picker. But I failed to add it when the user rotate the wheel to select new row and also to remove it from the previously added row. Any help would be appreciated.
  Thanks, </p>