I've just realized that the persist feature has lost some functionality
in the transition from 4.x to 5.x. I've tried both the Qt and X11
terminal, they behave the same in that respect.
$ gnuplot -p -e 'plot sin(x)'
With 4.x, resizing the window after the gnuplot main process has exited
will fit the existing plot to the window. That doesn't work with 5.x
anymore, it seems to try to keep the aspect ratio of the plot.
Is there an option I've not found that re-enables that feature or is
that a regression that could be fixed?