Hi. I'm attaching a gnuplot script that shows problematic behavior. Running that script produces a "correct" plot. Note that the ymin = 0, which is what you'd expect for a histogram plot. A 'replot' command causes the y extents to be recomputed, and ymin ends up at a completely different place, causing the rightmost bar to disappear entirely. As a user, I'd expect a replot to not make any visible changes.
Thanks
dima
The problem here comes from using volatile data + smoothing.
Looks like all the "smooth" options that reorder or replace the original data need to disable "refresh" and also hence also the replotting of volatile data.