Minor fixes

Author: dy

src/plot_api/plot_api.js

@@ -2796,6 +2796,7 @@ function makePlotFramework(gd) {
     // right, rather than enter/exit which can muck up the order
     // TODO: sort out all the ordering so we don't have to
     // explicitly delete anything
+    // FIXME: parcoords reuses this object, not the best pattern
     fullLayout._glcontainer = fullLayout._paperdiv.selectAll('.gl-container')
         .data([{}]);
     fullLayout._glcontainer.enter().append('div')

src/plots/plots.js

@@ -1332,7 +1332,7 @@ plots.purge = function(gd) {
 
     var fullLayout = gd._fullLayout || {};
     if(fullLayout._glcontainer !== undefined) {
-        fullLayout._glcontainer.selectAll('.gl-canvas').data([]).exit().remove();
+        fullLayout._glcontainer.selectAll('.gl-canvas').remove();
         fullLayout._glcontainer.remove();
         fullLayout._glcanvas = null;
     }