Don't update TrackAnalysis when tab is hidden

- add missing show/hide methods called by sidebar and maintain active state
- rename inconsistent tab id

index.html

@@ -791,7 +791,7 @@
                     </li>
                     <li>
                         <a
-                            href="#tab_statistics"
+                            href="#tab_analysis"
                             role="tab"
                             data-i18n="[title]sidebar.tab-tooltip"
                             data-i18n-options='{
@@ -995,7 +995,7 @@
                             <div id="itinerary" class="flexcolumn flexgrow"></div>
                         </div>
 
-                        <div class="leaflet-sidebar-pane" id="tab_statistics">
+                        <div class="leaflet-sidebar-pane" id="tab_analysis">
                             <h1 class="leaflet-sidebar-header">
                                 <span data-i18n="sidebar.analysis.title">Analysis</span>
                                 <span class="leaflet-sidebar-close"><i class="fa fa-caret-right"></i></span>

js/control/TrackAnalysis.js

@@ -50,6 +50,28 @@ BR.TrackAnalysis = L.Class.extend({
      */
     trackPolyline: null,
 
+    /**
+     * true when tab is shown, false when hidden
+     *
+     * @type {boolean}
+     */
+    active: false,
+
+    /**
+     * Called by BR.Sidebar when tab is activated
+     */
+    show: function() {
+        this.active = true;
+        this.options.requestUpdate(this);
+    },
+
+    /**
+     * Called by BR.Sidebar when tab is deactivated
+     */
+    hide: function() {
+        this.active = false;
+    },
+
     /**
      * Everytime the track changes this method is called:
      *
@@ -63,6 +85,10 @@ BR.TrackAnalysis = L.Class.extend({
      * @param {Array} segments
      */
     update: function(polyline, segments) {
+        if (!this.active) {
+            return;
+        }
+
         if (segments.length === 0) {
             $('#track_statistics').html('');
             return;