Fix background events for d3.svg.brush.

This reverts previous IE9 fixes to @4f552825.

d3.v2.js

@@ -10,7 +10,7 @@ try {
     d3_style_setProperty.call(this, name, value + "", priority);
   };
 }
-d3 = {version: "2.9.0"}; // semver
+d3 = {version: "2.9.1"}; // semver
 function d3_class(ctor, properties) {
   try {
     for (var key in properties) {
@@ -4404,7 +4404,6 @@ d3.svg.brush = function() {
 
     // Propagate the active cursor to the body for the drag duration.
     g.style("pointer-events", "none").selectAll(".resize").style("display", null);
-    g.select(".background").style("display", "none"); // workaround for IE9 bug
     d3.select("body").style("cursor", eventTarget.style("cursor"));
 
     // Notify listeners.
@@ -4529,7 +4528,6 @@ d3.svg.brush = function() {
 
       // reset the cursor styles
       g.style("pointer-events", "all").selectAll(".resize").style("display", brush.empty() ? "none" : null);
-      g.select(".background").style("display", null); // workaround for IE9 bug
       d3.select("body").style("cursor", null);
 
       w .on("mousemove.brush", null)

package.json

 {
   "name": "d3",
-  "version": "2.9.0",
+  "version": "2.9.1",
   "description": "A small, free JavaScript library for manipulating documents based on data.",
   "keywords": [
     "dom",

src/core/core.js

-d3 = {version: "2.9.0"}; // semver
+d3 = {version: "2.9.1"}; // semver

src/svg/brush.js

@@ -123,7 +123,6 @@ d3.svg.brush = function() {
 
     // Propagate the active cursor to the body for the drag duration.
     g.style("pointer-events", "none").selectAll(".resize").style("display", null);
-    g.select(".background").style("display", "none"); // workaround for IE9 bug
     d3.select("body").style("cursor", eventTarget.style("cursor"));
 
     // Notify listeners.
@@ -248,7 +247,6 @@ d3.svg.brush = function() {
 
       // reset the cursor styles
       g.style("pointer-events", "all").selectAll(".resize").style("display", brush.empty() ? "none" : null);
-      g.select(".background").style("display", null); // workaround for IE9 bug
       d3.select("body").style("cursor", null);
 
       w .on("mousemove.brush", null)