diff --git a/index.html b/index.html
index ef149c0..8c9eb14 100644
--- a/index.html
+++ b/index.html
@@ -16,6 +16,7 @@
         <link rel="apple-touch-icon" sizes="144x144" href="img/apple-touch-icon.png" />
         <link rel="fluid-icon" href="img/fluidicon.png" title="Mobile Tracker" />
         <link rel="icon" type="image/x-icon" href="favicon.ico" />
+        
         <!--
         <link rel="stylesheet" href="css/base.css"/>
         <link rel="stylesheet" href="css/skeleton.css"/>
@@ -23,6 +24,7 @@
         <link rel="stylesheet" href="css/habitat-font.css"/>
         <link rel="stylesheet" href="css/main.css"/>
         -->
+        
         <link rel="stylesheet" href="css/mobile.css"/>
     </head>
     <body>
@@ -154,6 +156,13 @@ <h2><i class="icon-settings rfloat"></i>Settings</h2>
                     <input type="checkbox" id="opt_hilight_vehicle">
                 </div>
             </div>
+            <div class="row option">
+                <span><b>Hide Horizon Rings</b></span>
+                <div class="switch off" id="sw_hide_horizon">
+                    <span class="thumb"></span>
+                    <input type="checkbox" id="opt_hide_horizon">
+                </div>
+            </div>
             <h4>Overlays</h4>
             <hr/>
             <div class="row option">
@@ -304,7 +313,7 @@ <h2>Chase car mode</h2>
     </div>
     <script src="https://maps.google.com/maps/api/js?v=3.31&libraries=map,common,controls,util,marker,onion,kml,ga,infowindow,stats,poly,overlay,weather,weather_impl,geometry&language=en_us&key=AIzaSyCOqkcNey4CCyG4X0X5qxHAhCgD8g5DwXg" type="text/javascript"></script>
     <script type="text/javascript" language="javascript" src="js/mobile.js"></script>
-<!--
+    <!--
     <script type="text/javascript" language="javascript" src="js/gmaps_extentions.js"></script>
     <script type="text/javascript" language="javascript" src="js/jquery-1.12.4-min.js"></script>
     <script type="text/javascript" language="javascript" src="js/chasecar.lib.js"></script>
@@ -312,7 +321,8 @@ <h2>Chase car mode</h2>
     <script type="text/javascript" language="javascript" src="js/nite-overlay.js"></script>
     <script type="text/javascript" language="javascript" src="js/tracker.js"></script>
     <script type="text/javascript" language="javascript" src="js/app.js"></script>
--->
+    -->
+
     <script type="text/javascript">
 
       var _gaq = _gaq || [];
diff --git a/js/app.js b/js/app.js
index 1a5f0f1..1e901ca 100644
--- a/js/app.js
+++ b/js/app.js
@@ -255,14 +255,19 @@ function trackerInit() {
 var initTimer = setTimeout(trackerInit, 3000);
 
 var cache = window.applicationCache;
-cache.addEventListener('noupdate', loadComplete, false);
-cache.addEventListener('updateready', loadComplete, false);
-cache.addEventListener('cached', loadComplete, false);
-cache.addEventListener('error', loadComplete, false);
+// TEMPORARILY DISABLED - MJ 2020-08-29
+// Application Cache is broken in recent chrome versions/
+// Disabling these addEventListener calls at least makes the rest of the page load.
+// Unsure what the implications of disabling these are.
+
+//cache.addEventListener('noupdate', loadComplete, false);
+//cache.addEventListener('updateready', loadComplete, false);
+//cache.addEventListener('cached', loadComplete, false);
+//cache.addEventListener('error', loadComplete, false);
 
 // if the browser supports progress events, display a loading bar
-cache.addEventListener('checking', function() { if(map && !force_check_cache) return; force_check_cache = false; clearTimeout(initTimer); $('#loading .bar,#loading').show(); $('#loading .complete').css({width: 0}); }, false);
-cache.addEventListener('progress', function(e) { $('#loading .complete').stop(true,true).animate({width: (200/e.total)*e.loaded}); }, false);
+//cache.addEventListener('checking', function() { if(map && !force_check_cache) return; force_check_cache = false; clearTimeout(initTimer); $('#loading .bar,#loading').show(); $('#loading .complete').css({width: 0}); }, false);
+//cache.addEventListener('progress', function(e) { $('#loading .complete').stop(true,true).animate({width: (200/e.total)*e.loaded}); }, false);
 
 var listScroll;
 var GPS_ts = null;
@@ -785,6 +790,7 @@ $(window).ready(function() {
         "#sw_hide_receivers",
         "#sw_hide_timebox",
         "#sw_hilight_vehicle",
+        '#sw_hide_horizon',
         "#sw_nowelcome",
         "#sw_interpolate",
     ];
@@ -845,6 +851,14 @@ $(window).ready(function() {
                     $('#lookanglesbox').css({top:'40px'});
                 }
                 break;
+            case "opt_hide_horizon":
+                if(on) {
+                    hideHorizonRings();
+                }
+                else {
+                    showHorizonRings();
+                }
+                break;
             case "opt_layers_aprs":
                 if(on) map.overlayMapTypes.setAt("1", overlayAPRS);
                 else map.overlayMapTypes.setAt("1", null);
diff --git a/js/tracker.js b/js/tracker.js
index c655488..b6eb2ba 100644
--- a/js/tracker.js
+++ b/js/tracker.js
@@ -44,6 +44,7 @@ var modeList = [
 //    "Position",
     "1 hour",
     "6 hours",
+    "12 hours",
     "1 day",
     "3 days",
     "All",
@@ -1655,6 +1656,12 @@ function addPosition(position) {
                 },
                 title: vcallsign,
             });
+
+            google.maps.event.addDomListener(marker, 'click', function() {
+                $(".row.active").removeClass('active');
+                $(".vehicle"+vehicles[marker.title].uuid).addClass('active');
+            });
+
             gmaps_elements.push(marker);
             marker.shadow = marker_shadow;
             marker.balloonColor = (vcallsign == "PIE") ? "rpi" : balloon_colors_name[color_index];
@@ -1679,10 +1686,13 @@ function addPosition(position) {
                     };
                 } else {
                     vehicle.marker.shadow.setVisible(true);
-                    vehicle.horizon_circle.setVisible(true);
-                    vehicle.horizon_circle.label.set('visible', true);
-                    vehicle.subhorizon_circle.setVisible(true);
-                    vehicle.subhorizon_circle.label.set('visible', true);
+
+                    if(offline.get('opt_hide_horizon') == false){
+                        vehicle.horizon_circle.setVisible(true);
+                        vehicle.horizon_circle.label.set('visible', true);
+                        vehicle.subhorizon_circle.setVisible(true);
+                        vehicle.subhorizon_circle.label.set('visible', true);
+                    }
 
                     if(mode == "parachute") {
                         img = {
@@ -1708,7 +1718,6 @@ function addPosition(position) {
             };
 
             // Add landing marker if the payload provides a predicted landing position.
-            // TODO: Only create this if the lat/lon are not zero.
             if (position.data.hasOwnProperty('pred_lat') && position.data.hasOwnProperty('pred_lon')){
                 // Only create the marker if the pred lat/lon are not zero (as will be the case during ascent).
                 if ((position.data.pred_lat !== 0.0) && (position.data.pred_lon !== 0.0)){
@@ -1815,6 +1824,13 @@ function addPosition(position) {
             google.maps.event.addListener(subhorizon_circle, 'center_changed', refresh_func);
             google.maps.event.addListener(subhorizon_circle, 'radius_changed', refresh_func);
 
+            if(offline.get("opt_hide_horizon")){
+                horizon_circle.setVisible(false);
+                horizon_circle.label.set('visible', false);
+                subhorizon_circle.setVisible(false);
+                subhorizon_circle.label.set('visible', false);
+            }
+
             marker.setAltitude(0);
             polyline_visible = true;
             polyline = [
@@ -2803,6 +2819,28 @@ function refreshUI() {
     if(follow_vehicle !== null) update_lookangles(follow_vehicle);
 }
 
+
+function hideHorizonRings(){
+    for(var vcallsign in vehicles) {
+        if(vehicles[vcallsign].vehicle_type == "balloon"){
+            vehicles[vcallsign].horizon_circle.setVisible(false);
+            vehicles[vcallsign].horizon_circle.label.set('visible', false);
+            vehicles[vcallsign].subhorizon_circle.setVisible(false);
+            vehicles[vcallsign].subhorizon_circle.label.set('visible', false);
+        }
+    }
+}
+function showHorizonRings(){
+    for(var vcallsign in vehicles) {
+        if(vehicles[vcallsign].vehicle_type == "balloon"){
+            vehicles[vcallsign].horizon_circle.setVisible(true);
+            vehicles[vcallsign].horizon_circle.label.set('visible', true);
+            vehicles[vcallsign].subhorizon_circle.setVisible(true);
+            vehicles[vcallsign].subhorizon_circle.label.set('visible', true);
+        }
+    }
+}
+
 var ssdv = {};
 var status = "";
 var bs_idx = 0;
