Latex in subplot title

I am unable to have LaTeX correctly render in a subplot title. Here is my example code:


eq_proj="-JW180/3i -Rg"
np_proj="-JG0/90/1.5i -R-180/180/40/90"
sp_proj="-JG180/-90/1.5i -R/-180/180/-90/-40"

gmt begin Figure png
  gmt set FONT_TAG 16p,Times-Italic
  gmt set FONT_TITLE 16p,Helvetica

  gmt subplot begin 1x2 -Fs${SUBPLOT_WIDTH1},${SUBPLOT_WIDTH2},${SUBPLOT_WIDTH2}/${SUBPLOT_HEIGHT} -A+o-0.2c/0 -M0.4c/0.3c

    gmt subplot set 0,0 -A"@[\nabla^2@["
    gmt basemap ${eq_proj} -B0

    gmt subplot set 0,1 -A-
    gmt basemap ${np_proj}

  gmt subplot end

gmt end show

And here is the result:

Can anyone spot the problem?

Using Latex in subplot panel tags was never implemented. I just tried to do it but it is tricky since the tags are plotted after everything in the panel is plotted so we must create a PostScript function in the subplot -A call and then call that PostScript function at the end of the panel. This yields a PostScript error - trying to figure it out.

Meantime I suggest you place such text via text.