update elements and fix some bugs

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

 <!--
 Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 -->
 
 <link rel="import" href="../polymer/polymer.html">
@@ skipping 38 matching lines @@
        * If you want to use the attribute value of an element for `selected` instead of the index,
        * set this to the name of the attribute.
        */
       attrForSelected: {
         type: String,
         value: null
       },
 
       /**
        * Gets or sets the selected element. The default is to use the index of the item.
-       *
-       * @type {string|number}
        */
       selected: {
         type: String,
         notify: true
       },
 
       /**
        * Returns the currently selected item.
        */
       selectedItem: {
@@ skipping 29 matching lines @@
 
       /**
        * The attribute to set on elements when selected.
        */
       selectedAttribute: {
         type: String,
         value: null
       },
 
       /**
-       * 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 {
             'template': 1
           };
         }
       }
     },
 
     observers: [
       '_updateSelected(attrForSelected, selected)'
     ],
 
     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() {
       if (this._observer) {
         this._observer.disconnect();
       }
       if (this._contentObserver) {
         this._contentObserver.disconnect();
       }
       this._removeListener(this.activateEvent);
@@ skipping 46 matching lines @@
      * Selects the next item.
      *
      * @method selectNext
      */
     selectNext: function() {
       var index = (Number(this._valueToIndex(this.selected)) + 1) % this.items.length;
       this.selected = this._indexToValue(index);
     },
 
     _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) {
       this._removeListener(old);
       this._addListener(eventName);
     },
 
     _updateSelected: function() {
       this._selectSelected(this.selected);
     },
 
     _selectSelected: function(selected) {
       this._selection.select(this._valueToItem(this.selected));
     },
 
     _filterItem: function(node) {
-      return !this.excludedLocalNames[node.localName];
+      return !this._excludedLocalNames[node.localName];
     },
 
     _valueToItem: function(value) {
       return (value == null) ? null : this.items[this._valueToIndex(value)];
     },
 
     _valueToIndex: function(value) {
       if (this.attrForSelected) {
         for (var i = 0, item; item = this.items[i]; i++) {
           if (this._valueForItem(item) == value) {
@@ skipping 82 matching lines @@
     _itemActivate: function(value, item) {
       if (!this.fire('iron-activate',
           {selected: value, item: item}, {cancelable: true}).defaultPrevented) {
         this.select(value);
       }
     }
 
   };
 
 </script>