Merge pull request #1479 from plotly/gc-regl-context

Let the regl object tree be garbage collected on `Plotly.restyle`

Author: monfera

src/traces/parcoords/base_plot.js

@@ -61,7 +61,6 @@ exports.toSVG = function(gd) {
         });
     }
 
-    imageRoot.selectAll('*').remove();
     canvases.each(canvasToImage);
 
     // Chrome / Safari bug workaround - browser apparently loses connection to the defined pattern

src/traces/parcoords/parcoords.js

@@ -278,11 +278,11 @@ module.exports = function(root, svg, styledData, layout, callbacks) {
         .map(model.bind(0, layout))
         .map(viewModel);
 
+    root.selectAll('.parcoords-line-layers').remove();
+
     var parcoordsLineLayers = root.selectAll('.parcoords-line-layers')
         .data(vm, keyFun);
 
-    parcoordsLineLayers.exit().remove();
-
     parcoordsLineLayers.enter()
         .insert('div', '.' + svg.attr('class').split(' ').join(' .')) // not hardcoding .main-svg
         .classed('parcoords-line-layers', true)