From 425513b7297da4f194a8595d1f0a4169afb79769 Mon Sep 17 00:00:00 2001
From: Andrew n marshall <Anm@anm.me>
Date: Wed, 22 Jun 2016 13:11:19 -0700
Subject: [PATCH] Don't output blockId if not set (e.g., toolbox category
 event). (#443)

---
 core/events.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/core/events.js b/core/events.js
index f1971478d..f78222d03 100644
--- a/core/events.js
+++ b/core/events.js
@@ -303,8 +303,10 @@ Blockly.Events.Abstract = function(block) {
 Blockly.Events.Abstract.prototype.toJson = function() {
   var json = {
     'type': this.type,
-    'blockId': this.blockId
   };
+  if (this.blockId) {
+    json['blockId'] = this.blockId;
+  }
   if (this.group) {
     json['group'] = this.group;
   }