diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/src/core/dispatch.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/src/core/dispatch.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,57 @@
+d3.dispatch = function() {
+  var dispatch = new d3_dispatch(),
+      i = -1,
+      n = arguments.length;
+  while (++i < n) dispatch[arguments[i]] = d3_dispatch_event();
+  return dispatch;
+};
+
+function d3_dispatch() {}
+
+d3_dispatch.prototype.on = function(type, listener) {
+  var i = type.indexOf("."),
+      name = "";
+
+  // Extract optional namespace, e.g., "click.foo"
+  if (i > 0) {
+    name = type.substring(i + 1);
+    type = type.substring(0, i);
+  }
+
+  this[type].on(name, listener);
+};
+
+function d3_dispatch_event() {
+  var listeners = [],
+      listenerByName = {};
+
+  function dispatch() {
+    var z = listeners, // defensive reference
+        i = -1,
+        n = z.length,
+        l;
+    while (++i < n) if ((l = z[i])._on) l.apply(this, arguments);
+  }
+
+  dispatch.on = function(name, listener) {
+    var l, i;
+
+    // remove the old listener, if any
+    if (l = listenerByName[name]) {
+      l._on = false;
+      listeners = listeners.slice(0, i = listeners.indexOf(l)).concat(listeners.slice(i + 1));
+      delete listenerByName[name];
+    }
+
+    // add the new listener, if any
+    if (listener) {
+      listener._on = true;
+      listeners.push(listener);
+      listenerByName[name] = listener;
+    }
+
+    return dispatch;
+  };
+
+  return dispatch;
+};