Properly retain original opacity of 0 (0 is falsy in JavaScript), closes #1406

Author: cpsievert

inst/htmlwidgets/plotly.js

@@ -522,7 +522,7 @@ function TraceManager(graphDiv, highlight) {
   // avoid doing this over and over
   this.origOpacity = [];
   for (var i = 0; i < this.origData.length; i++) {
-    this.origOpacity[i] = this.origData[i].opacity || 1;
+    this.origOpacity[i] = this.origData[i].opacity === 0 ? 0 : (this.origData[i].opacity || 1);
   }
 
   // key: group name, value: null or array of keys representing the
@@ -603,7 +603,7 @@ TraceManager.prototype.updateSelection = function(group, keys) {
 
   if (keys === null) {
 
-    Plotly.restyle(this.gd, {"opacity": this.origOpacity});
+    Plotly.restyle(this.gd, {"opacity": this.acity});
 
   } else if (keys.length >= 1) {
 
@@ -741,7 +741,7 @@ TraceManager.prototype.updateSelection = function(group, keys) {
           n = this.origData.length;
 
       for (var i = 0; i < n; i++) {
-        var opacity = this.origOpacity[i] || 1;
+        var opacity = this.acity[i] || 1;
         // have we already dimmed this trace? Or is this even worth doing?
         if (opacity !== this.gd._fullData[i].opacity || this.highlight.opacityDim === 1) {
           continue;