From 82a4f9c3664056aca276c0839fb42db5670217e0 Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Tue, 4 Jun 2013 18:33:23 -0700
Subject: [PATCH] Avoid duplicate hover events

---
 js/id/behavior/hover.js | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/js/id/behavior/hover.js b/js/id/behavior/hover.js
index 2ddb2eaf7..fd2209d56 100644
--- a/js/id/behavior/hover.js
+++ b/js/id/behavior/hover.js
@@ -34,8 +34,15 @@ iD.behavior.Hover = function(context) {
     var hover = function(__) {
         selection = __;
 
-        function mouseover() {
-            target = d3.event.target.__data__;
+        function enter(d) {
+            if (d === target) return;
+
+            target = d;
+
+            selection.selectAll('.hover')
+                .classed('hover', false);
+            selection.selectAll('.hover-suppressed')
+                .classed('hover-suppressed', false);
 
             if (target && target.type) {
                 var selector = '.' + target.id;
@@ -52,17 +59,19 @@ iD.behavior.Hover = function(context) {
                     .classed(suppressed ? 'hover-suppressed' : 'hover', true);
 
                 dispatch.hover(target.id);
+            } else {
+                dispatch.hover(null);
             }
         }
 
-        function mouseout() {
-            dispatch.hover(null);
-            target = null;
+        function mouseover() {
+            var target = d3.event.target;
+            enter(target ? target.__data__ : null);
+        }
 
-            selection.selectAll('.hover')
-                .classed('hover', false);
-            selection.selectAll('.hover-suppressed')
-                .classed('hover-suppressed', false);
+        function mouseout() {
+            var target = d3.event.relatedTarget;
+            enter(target ? target.__data__ : null);
         }
 
         selection