I have a problem with 4.1.2

I set up a grid combining the following samples at http://www.trirand.com/blog/jqgrid/jqgrid.html

New in version 3.5 / Integrated Search Toolbar

and

New in version 3.6 / True scrolling Rows

The problem occurs when:

1) I scroll down and I load a big chunk of rows with several different ajax requests to the server

2) I filter a column so that the result has two or three rows

In this case the table is not top alligned and between the column headers and the start of the table containing the rows there is a div with height around 200px