grid is showing empty space between rows

We are trying to display 30000 records using dhtmlxgrid. But there is empty space in between the rows. We are using the following syntax to load the xml data…

    mygrid.loadXML("…/VisualDisplay.xml");

The xml file is containing all the records correctly but the rows are not getting displayed correctly. But still there is empty space between the rows i.e some of the rows are not geeting displayed. The code is as follows

mygrid = new dhtmlXGridObject(‘custDiv’);

    mygrid.setImagePath("…/images/dhtmlxgrid/");

    mygrid.setHeader(", Customer Number, Customer Name");

    mygrid.setInitWidths(“80,150,150”);    

    mygrid.setColAlign(“right,left,left”);    

    mygrid.setColTypes(“ch,txt,txt”);

    mygrid.setSkin(“modern”);

    mygrid.init();

    mygrid.enableSmartRendering(true,2000,50);

    mygrid.loadXML("…/VisualDisplay.xml");

a) The issue can be caused by using custom CSS, which change default row height. The SmartRendering mode based on fixed height of row, if you are using some customized css , which changes height of rows, you need to defined new value as
    grid.setAwaitedRowHeight(25); // where 25 - new row height.

b) The enableSmartRendering(true,2000,50); says, that grid must expect only 2000 rows.
You may not specify any parameters here
    enableSmartRendering(true);// or in case of grid 1.6 enableSmartRendering(true,50);
and specify correct count or rows through rows@total_count attribute in XML