jQuery Grid Plugin - jqGrid

Hi, I am testing your really cool jqgrid tool and I have found a curious behaviour that seems to be a bug.

For my page, I need a grid with virtual scrolling with only visible rows kept in local jqgrid cache.

So i test the virtual scrolling demo (http://trirand.com/blog/jqgrid.....qgrid.html /  New in version 3.7  / Virtual scrolling) and I found a strange behaviour :

When scrolling the table using the scrollbar bottom arrow button with multiple clicks, rows are kept in the jqgrid local cache (see the rows index in the pager) whereas when scrolling it with the slider, rows are correctly cleared.

I think this is a bug because the documentation says :

When scroll is set to an integer value (example 1), the grid will just hold the visible lines.

In this case the grid holds all the previous displayed lines.