Smart Rendering problems in c# mvc4

We have a pro license for dhtmlxgrid 3.0 and have used it successfully in php for a number of years.

I am now looking to use it in .NET MVC4 and am having issues.

Steps to reproduce:

  1. Modify the sample “14_loading_big_datasets/03_grid_dyn.html” to load from the ajax controller:
  1. Configure the following actionresult in the controller:

[code]public ActionResult ModelTest(int posStart = 0, int count = 50)
String XMLString = String.Format(@"<rows total_count=""{0}"" pos=""{1}"">", “1000”, posStart.ToString());
for (int i = 0; i < count; i++)
XMLString += String.Format(@"<row id="“r{0}”">{1}{2}{3}", i + posStart, i + posStart, i, “blah2”);
XMLString += “”;

        Response.AppendHeader("Content-type", "text/xml");
        return this.Content("<?xml version='1.0' encoding='iso-8859-1'?>" + XMLString, "text/xml", System.Text.Encoding.UTF8); 

The grid loads initiall, but then goes blank after I scroll past the 49th row…