draw grids only in the mainplot

Author: archmoj

src/plots/cartesian/index.js

@@ -568,7 +568,7 @@ function makeSubplotLayer(gd, plotinfo) {
     var yLayer = constants.layerValue2layerClass[plotinfo.yaxis.layer];
     var hasOnlyLargeSploms = fullLayout._hasOnlyLargeSploms;
 
-    if(!plotinfo.mainplot || fullLayout._zindices.length > 1) {
+    if(!plotinfo.mainplot) {
         if(hasOnlyLargeSploms) {
             // TODO could do even better
             // - we don't need plot (but we would have to mock it in lsInner