update elements and fix some bugs

lib/src/iron-selector/iron-selectable.html

Index: lib/src/iron-selector/iron-selectable.html
diff --git a/lib/src/iron-selector/iron-selectable.html b/lib/src/iron-selector/iron-selectable.html
index 26bb2655148af3dbcabcee0601b249e545c9b120..eb1fb5fd431ab6e2548b92892004477d3143cad4 100644
--- a/lib/src/iron-selector/iron-selectable.html
+++ b/lib/src/iron-selector/iron-selectable.html
@@ -56,8 +56,6 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 
       /**
        * Gets or sets the selected element. The default is to use the index of the item.
-       *
-       * @type {string|number}
        */
       selected: {
         type: String,
@@ -107,12 +105,13 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
       },
 
       /**
-       * The set of excluded elements where the key is the `localName` 
+       * The set of excluded elements where the key is the `localName`
        * of the element that will be ignored from the item list.
        *
+       * @type {object}
        * @default {template: 1}
        */
-      excludedLocalNames: {
+      _excludedLocalNames: {
         type: Object,
         value: function() {
           return {
@@ -129,11 +128,18 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     created: function() {
       this._bindFilterItem = this._filterItem.bind(this);
       this._selection = new Polymer.IronSelection(this._applySelection.bind(this));
+      // TODO(cdata): When polymer/polymer#2535 lands, we do not need to do this
+      // book keeping anymore:
+      this.__listeningForActivate = false;
     },
 
     attached: function() {
       this._observer = this._observeItems(this);
       this._contentObserver = this._observeContent(this);
+      if (!this.selectedItem && this.selected) {
+        this._updateSelected(this.attrForSelected,this.selected)
+      }
+      this._addListener(this.activateEvent);
     },
 
     detached: function() {
@@ -200,11 +206,17 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     },
 
     _addListener: function(eventName) {
+      if (!this.isAttached || this.__listeningForActivate) {
+        return;
+      }
+
+      this.__listeningForActivate = true;
       this.listen(this, eventName, '_activateHandler');
     },
 
     _removeListener: function(eventName) {
       this.unlisten(this, eventName, '_activateHandler');
+      this.__listeningForActivate = false;
     },
 
     _activateEventChanged: function(eventName, old) {
@@ -221,7 +233,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     },
 
     _filterItem: function(node) {
-      return !this.excludedLocalNames[node.localName];
+      return !this._excludedLocalNames[node.localName];
     },
 
     _valueToItem: function(value) {