Hi Tony,
I had the same problem. I think solution is pretty simple, if I change:
Ln279: //page = parseInt((tbot + scrollTop) / div) + 1; // Original code
to
Ln279: page = parseInt((tbot + scrollTop + div – 1) / div) + 1; //changed code
in grid.base.js, everything works fine.
Also I found a problem: when grid uses 'altrows:true' scrolling doesn't work. I did a workaround by adding
scrollTop -= (rows.outerHeight() – rows.innerHeight()) * rn;
after ln271.