title: JQGrid Form Edit disable dropdown on Edit but not Add
body: <p>I am creating a grid with a dropdown (select) populated by editoptions{dataUrl:'myUrl'}.  The issue I am having is I need to disable this dropdown (or alternatively, remove it from the edit form and in its place add the Column Name: Value in text format).  I only want to disable this in the edit form though.  </p>
  
  <p>I've tried the afterShowForm event, but that doesn't work because afterShowForm is fired before the data is fetched from the dataUrl.  </p>
  
  <p>The dataInit option for editoptions seems like it would be convoluted to manipulate correctly, as it needs to occur for just edits, and not adds (need to change the functions somehow).</p>
  
  <p>What other methods are there?</p>