Maxima 5.25.1 on Mac gnuplot problem - no window



Trying a simple command which should invoke gnuplot (and does on a windows machine) like:

load("draw");
draw3d(surface_hide=true,color=red,implicit(5*x+y+z=3,x,-1,1,y,-1,1,z,-1,1));

gives just

[gr3d(implicit)]

and no other output. 
I tried some recent older versions but to no success, but I remember it working some years ago.

Any hint?