Persistent confusion about gnuplot -persist

[Ethan A M. <sf...@us...>]

There have recently been several queries, bug reports, support requests,
and so on that involve misunderstanding about what to expect from 
gnuplot -persist    or    set term <foo> persist.

People seem to assume that if the window is still showing on the screen,
they should be able to pan/zoom/unzoom and so on using the mouse
buttons or the widgets at the top of the terminal GUI.   

The documentation is quite explicit that this isn't true in general because
such operations require the main program to recalculate and redraw the
plot, which cannot happen in -persist mode because the main program
has already exited.     As it happens, the wxt terminal back in version 4.4
was an exception to this general case.  I guess people remember that 
exception and want to generalize it to all current terminals.

That is, people expect this

    [1] gnuplot -persist -e "plot sinh(x); exit"

to act like this

    [2] gnuplot -e "plot sinh(x); pause mouse close; exit" &

The question is, should we continue pointing to the documented limitations
of "persist", or should we change what persist does to match people's
expectation?   

So far as I know [2] works properly for the x11, wxt, and qt terminals
under linux.  I don't know about MSWin (win) or OSX (aqua).

Assuming that [2] can be made to work correctly on all three of these
platforms, should we reimplement "set term ... persist" and "gnuplot -persist"
to act like this instead of retaining the current implementation?

If so, is it worth holding up release of 5.0 until this change has been
implemented and tested?

	Ethan