Nobody knows nothing?
Still nada...still having the problem.
I tried turning off the 'keep records sorted' option on the last sort script step, but that didn't seem to help.
Another weird aspect of this is that the jumping behavior seems to be restricted to a certain sub-set of the records. E.g. if I click on a row from 6-10, after scrolling it into view (because you can only see about 3 rows at a time on this layout), the scroll position and rendering of the layout will jump around and show you row 2. But if I click on rows 11 - 40 no jumping around happens.
Perhaps related to the original problem, a co-worker did notice that using Safari (on OS X 10...?) they are simply scrolling through the display (no clicking on records) and when they stop scrolling the displayed records jump 3-4 records away. Happens when scrolling up or down in the list. This happens for me as well (Safari, 10.9.5).
I also see behavior where the graphic for the scroll bar is jumping around and changing sizes, but the visible content isn't changing.
At other times it scrolls, the whole page goes blank and the loading spinner shows up, then redisplays - a la a screen redraw.
Is this an issue with it loading another chunk of records?
(There's an error in my original post; this file is hosted on FMS 14.04.)