From 9cdf0cdd6614e65c6375b3561ad4f014ab0a156b Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Thu, 8 Jun 2017 13:13:46 -0400
Subject: [PATCH] Add explict check for prototype inheritance of entities
 Chrome bug (see #3973)

---
 modules/core/graph.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/modules/core/graph.js b/modules/core/graph.js
index 27b575164..7d168b35c 100644
--- a/modules/core/graph.js
+++ b/modules/core/graph.js
@@ -34,6 +34,12 @@ coreGraph.prototype = {
 
     entity: function(id) {
         var entity = this.entities[id];
+
+        //https://github.com/openstreetmap/iD/issues/3973#issuecomment-307052376
+        if (!entity) {
+            entity = this.entities.__proto__[id];
+        }
+
         if (!entity) {
             throw new Error('entity ' + id + ' not found');
         }