There are two terminal types for gnuplot that I know of, one is win, the other is wxt.
wxt has more functions than win and is therefore preferred.
To make sure octave uses wxt instead of win, simply set the environment variable GNUTERM = wxt by "right clicking My computer - Advanced - Environment Variables", remember to restart octave.
And it is possible that the plot terminal might freeze for some reason. One work-around to this is to add the following commands
to the end of the script.