Required library edition:
Required library file: dhtmlxgrid_fast.js

turn off fast operation mode, need to be executed to normalize view.

   mygrid.startFastOperations();
 
   for (var i=0; i<1000; i++)
       mygrid.addRow(mygrid.uid(),[i,"new row"]);
 
   mygrid.stopFastOperations();

See also: startFastOperations