From af37d04c8b7d2562d271b6478e00652211c21280 Mon Sep 17 00:00:00 2001
From: Daniel Freedman <dfreedm@google.com>
Date: Tue, 4 Apr 2017 12:07:22 -0700
Subject: [PATCH] Only check bounding client rect on clicks that target
 elements

Fixes #4459
---
 lib/utils/gestures.html |  5 +++++
 test/unit/gestures.html | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/lib/utils/gestures.html b/lib/utils/gestures.html
index e4599758c2..c81b51cd6f 100644
--- a/lib/utils/gestures.html
+++ b/lib/utils/gestures.html
@@ -150,6 +150,11 @@
       // the bounding box of the target of the event
       // Thanks IE 10 >:(
       let t = Gestures._findOriginalTarget(ev);
+      // make sure the target of the event is an element so we can use getBoundingClientRect,
+      // if not, just assume it is a synthetic click
+      if (t.nodeType !== Node.ELEMENT_NODE) {
+        return true;
+      }
       let bcr = t.getBoundingClientRect();
       // use page x/y to account for scrolling
       let x = ev.pageX, y = ev.pageY;
diff --git a/test/unit/gestures.html b/test/unit/gestures.html
index 868961910c..289de18e61 100644
--- a/test/unit/gestures.html
+++ b/test/unit/gestures.html
@@ -506,6 +506,16 @@
         assert.equal(el[key], 'pan-y');
       })
     });
+
+    suite('Regression Testing', function() {
+      test('#4459', function() {
+        Polymer.Gestures.add(document, 'tap', null);
+        document.dispatchEvent(new MouseEvent('mousedown', { detail: 1, clientX: -100, bubbles: true, composed: true }));
+        document.dispatchEvent(new MouseEvent('mouseup', { detail: 1, clientX: 100, bubbles: true, composed: true }));
+        document.dispatchEvent(new MouseEvent('click', { detail: 1, clientX: 100, bubbles: true, composed: true }));
+        Polymer.Gestures.remove(document, 'tap', null);
+      });
+    })
   </script>
 
 </body>