grid go blank when scrolling...

can I increase the buffer rows more than 20?
refer to the following topic, I could not find the code. I'm using 2.5.3 now.
http://www.activewidgets.com/javascript.forum.12781.3/aw-ui-grid-virtual-rendering.html

There is no public API to manipulate virtual scrolling parameters, except switching it on or off completely -

grid.setVirtualMode(true/false); // default is true

If you want to change the existing behavior you can modify the source code in /source/lib/grid/_virtual.js, line 38-39:

var delta1 = dir < 0 ? 10 : 1;
var delta2 = dir > 0 ? 10 : 1;

These two variables define the number of rows rendered above and below the visible area. By default this is 10 rows in the direction of scrolling and 0 on the opposite side. Both are 0 during the initial rendering and during the horizontal scroll.