Running openmath plots in the background



When I create a standard 2d plot of a function using plot2d (under linux), I
have a gnuplot window which remains open while I can continue to work in
maxima (using console maxima or imaxima in emacs).  However, if I use the
[plot_format,openmath] option, then the maxima process is halted while the
plot window is open; I can only perform further work in maxima by closing
the plot window.

How can I run an openmath window in the background, so to speak?  That is,
remain working with maxima while having a plot window open?

Thanks,
Alasdair