I've found an issue in the scroll=1 mode, where the content of the last page (et then end of the grid) isn't always requested.

This can be reproduced with FireFox 3.6 and Chrome in the “True Scrolling Rows” jqGrid demo with the following steps:

• move with the scrollbar near the bottom but not quite (around row #12086 is ok), if you fail to scroll there, scroll to the top, then try again
• scroll down using the down arrow of the scrollbar, you will hit #12100, ajax loading will happen for 100 rows, keep scrolling down with the arrow
• when you reach #12200, the lines will stay empty and no ajax loading will happen

It's possible to trigger the issue with the scrollbar slider only (without using the arrow), though on grids with smaller row count, and the conditions don't seem to be as reproducible.