dalanicolai@gmail.com writes:

> Now the solution is simple, just manually insert "ls" between "with
> lines" and the following number in the *Gnuplot Commands* buffer. Then
> plot again with `gp`, the graph will show with different linestyle.

Yup.  This should now be fixed in Emacs 28.

--
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   bloggy blog: http://lars.ingebrigtsen.no