--- a/scripts/plot/isosurface.m
+++ b/scripts/plot/isosurface.m
@@ -150,7 +150,7 @@
   endif
   if (calc_colors)
     if (nargout == 2)
-      warning ( "Colors will be calculated, but you did not specify an output argument for it!" );
+      warning ("isosurface: colors will be calculated, but no output argument to receive it.");
     endif
     [fvc.faces, fvc.vertices, fvc.facevertexcdata] = __marching_cube__ (x, y, z, val, iso, colors);
   else
@@ -158,13 +158,13 @@
   endif
 
   if (isempty (fvc.vertices) || isempty (fvc.faces))
-    warning ( "The resulting triangulation is empty" );
+    warning ("isosurface: triangulation is empty");
   endif
 
   switch (nargout)
     case 0
       ## plot the calculated surface
-      newplot ();
+      hax = newplot ();
       if (calc_colors)
         pa = patch ("Faces", fvc.faces, "Vertices", fvc.vertices,
                     "FaceVertexCData", fvc.facevertexcdata,
@@ -174,8 +174,8 @@
                     "FaceColor", "g", "EdgeColor", "k");
       endif
       if (! ishold ())
-        set (gca (), "view", [-37.5, 30],
-             "xgrid", "on", "ygrid", "on", "zgrid", "on");
+        set (hax, "view", [-37.5, 30],
+                  "xgrid", "on", "ygrid", "on", "zgrid", "on");
       endif
     case 1
       varargout = {fvc};
@@ -200,12 +200,14 @@
 %! [x, y, z]  = meshgrid (0:1, 0:1, 0:1); # Points for single
 %! val        = [0, 0; 0, 0];             # cube and a 3-D
 %! val(:,:,2) = [0, 0; 1, 0];             # array of values
+
 %!test
 %! fv = isosurface (x, y, z, val, 0.3);
 %! assert (isfield (fv, "vertices"), true);
 %! assert (isfield (fv, "faces"), true);
 %! assert (size (fv.vertices), [3 3]);
 %! assert (size (fv.faces), [1 3]);
+
 %!test
 %! fvc = isosurface (x, y, z, val, .3, y);
 %! assert (isfield (fvc, "vertices"), true);
@@ -214,10 +216,12 @@
 %! assert (size (fvc.vertices), [3 3]);
 %! assert (size (fvc.faces), [1 3]);
 %! assert (size (fvc.facevertexcdata), [3 1]);
+
 %!test
 %! [f, v] = isosurface (x, y, z, val, .3);
 %! assert (size (f), [1 3]);
 %! assert (size (v), [3 3]);
+
 %!test
 %! [f, v, c] = isosurface (x, y, z, val, .3, y);
 %! assert (size (f), [1 3]);