diff --git a/webgui/main.js b/webgui/main.js
index 8c9fec226..f28857f79 100644
--- a/webgui/main.js
+++ b/webgui/main.js
@@ -67,22 +67,48 @@ require([
         self.initWebsocket();
 
         self.fire = function(json) {
-            var koObservable = self.listeners[json.path] || null;
-            if (!koObservable)
-                return;
+            var value = json.value;
+            var listeners = self.listeners[json.path] || [];
+            listeners.forEach(function(koObservable) {
+                koObservable(value)
+            });
             koObservable(json.value);
         }
 
+        function resolvePropertyPath(self, pathOrAlias) {
+            if (pathOrAlias in self.aliases)
+                return self.aliases[pathOrAlias];
+            if (pathOrAlias.charAt(0) == '/')
+                return pathOrAlias;
+            return null;
+        }
+
         self.listeners = {}
 
-        self.getListener = function(pathOrAlias) {
-            if( pathOrAlias in self.listeners ) {
-                return self.listeners[pathOrAlias];
+        self.removeListener = function(pathOrAlias, koObservable) {
+            var path = resolvePropertyPath(self, pathOrAlias);
+            if (path == null) {
+                console.log("can't remove listener for " + pathOrAlias + ": unknown alias or invalid path.");
+                return self;
             }
-        }
 
-        self.removeListener = function(pathOrAlias) {
+            var listeners = self.listeners[path] || [];
+            var idx = listeners.indexOf(koObservable);
+            if (idx == -1) {
+                console.log("can't remove listener for " + path + ": not a listener.");
+                return self;
+            }
 
+            listeners.splice(idx, 1);
+
+            if (0 == listeners.length) {
+                self.ws.send(JSON.stringify({
+                    command : 'removeListener',
+                    node : path
+                }));
+            }
+
+            return self;
         }
 
         self.addListener = function(alias, koObservable) {
@@ -92,29 +118,35 @@ require([
                     "prop" : alias,
                     "koObservable" : koObservable
                 });
-                return;
+                return self;
             }
 
-            var path = this.aliases[alias] || "";
-            if (path.length == 0) {
-                if (alias.charAt(0) == '/') {
-                    path = alias;
-                } else {
-                    console.log("can't listen to " + alias + ": unknown alias.");
-                    return;
-                }
+            var path = resolvePropertyPath(self, alias);
+            if (path == null) {
+                console.log("can't listen to " + alias + ": unknown alias or invalid path.");
+                return self;
             }
 
-            self.listeners[path] = koObservable;
+            var listeners = self.listeners[path] = (self.listeners[path] || []);
+            if (listeners.indexOf(koObservable) != -1) {
+                console.log("won't listen to " + path + ": duplicate.");
+                return self;
+            }
 
-            self.ws.send(JSON.stringify({
-                command : 'addListener',
-                node : path
-            }));
+            listeners.push(koObservable);
+
+            if (1 == listeners.length) {
+                self.ws.send(JSON.stringify({
+                    command : 'addListener',
+                    node : path
+                }));
+            }
             self.ws.send(JSON.stringify({
                 command : 'get',
                 node : path
             }));
+
+            return self;
         }
 
         self.aliases = aliases || {};
@@ -365,9 +397,9 @@ require([
 
         update : function(element, valueAccessor, allBindings) {
             var value = valueAccessor() || {};
-            var data = ko.unwrap( value.data );
-            var options = ko.unwrap( value.options );
-            jquery.plot(element, data,  options );
+            var data = ko.unwrap(value.data);
+            var options = ko.unwrap(value.options);
+            jquery.plot(element, data, options);
 
         },
 
diff --git a/webgui/topics/Aircraft.js b/webgui/topics/Aircraft.js
index ee3122fd4..c78893c9f 100644
--- a/webgui/topics/Aircraft.js
+++ b/webgui/topics/Aircraft.js
@@ -17,6 +17,10 @@ define([
         require : 'topics/Aircraft/Help'
     });
 
+    ko.components.register('Aircraft/Panel', {
+        require : 'topics/Aircraft/Panel'
+    });
+
     function ViewModel(params) {
         var self = this;
         
diff --git a/webgui/topics/Aircraft/Help.html b/webgui/topics/Aircraft/Help.html
index fc790f896..828b17536 100644
--- a/webgui/topics/Aircraft/Help.html
+++ b/webgui/topics/Aircraft/Help.html
@@ -1,6 +1,10 @@
 <style>
 </style>
 
+<div class="ui-widget-content ui-corner-all" data-bind="if: longDescription().length">
+    <div class="ui-widget-header ui-corner-all" data-bind="text: description"></div>
+    <div data-bind="text: longDescription"></div>
+</div>
 <table id="phi-aircraft-helptable" class="ui-widget-content ui-corner-all">
     <caption class="ui-widget-header ui-corner-all" data-bind="text: helpTitle"></caption>
     <tbody data-bind="foreach: helpContent">
diff --git a/webgui/topics/Aircraft/Help.js b/webgui/topics/Aircraft/Help.js
index 30a634931..2304e7cde 100644
--- a/webgui/topics/Aircraft/Help.js
+++ b/webgui/topics/Aircraft/Help.js
@@ -6,6 +6,16 @@ define([
 
         self.helpTitle = ko.observable("");
         self.helpContent = ko.observableArray([]);
+        self.description = ko.observable('');
+        self.longDescription = ko.observable('');
+
+        jquery.get('/json/sim/description', null, function(data) {
+            self.description(data.value);
+        });
+
+        jquery.get('/json/sim/long-description', null, function(data) {
+            self.longDescription(data.value);
+        });
 
         jquery.get('/json/sim/help?d=2', null, function(data) {
 
diff --git a/webgui/topics/Simulator/Properties.js b/webgui/topics/Simulator/Properties.js
index d0399d72a..7241d41d0 100644
--- a/webgui/topics/Simulator/Properties.js
+++ b/webgui/topics/Simulator/Properties.js
@@ -11,8 +11,10 @@ define([
 
         this.samples = [];
         this.sample = function(timeStamp) {
-            while (this.samples.length >= this.maxSamples)
+            console.log(this.samples.length,this.maxSamples);
+            while (this.samples.length >= this.maxSamples) {
                 this.samples.shift();
+            }
             this.samples.push([
                     timeStamp, this.source()
             ]);
@@ -42,8 +44,9 @@ define([
         }
 
         this.removeSource = function(source) {
+            var s = this.sources[source].source;
             delete this.sources[source];
-            return this;
+            return s;
         }
 
         this.containsSource = function(source) {
@@ -242,19 +245,23 @@ define([
         self.toggleProp = function(prop) {
 
             if (self.propertySampler.containsSource(prop.path)) {
-                self.propertySampler.removeSource(prop.path);
+                var obs = self.propertySampler.removeSource(prop.path);
+                ko.utils.knockprops.removeListener(prop.path, obs);
                 return;
             }
 
-            var obs = ko.utils.knockprops.getListener(prop.path);
-            if (obs) {
-                self.propertySampler.addSource(new SampleSource(prop, obs, {
-                    maxSamples : 1000,
-                }));
-            }
+            var obs = ko.observable(0);
+            ko.utils.knockprops.addListener(prop.path, obs);
+            self.propertySampler.addSource(new SampleSource(prop, obs, {
+                maxSamples : 300,
+            }));
         }
 
-        self.update = function() {
+        self.updateId = 0;
+        self.update = function(id) {
+
+            if (self.updateId != id)
+                return;
 
             var sources = self.propertySampler.sources;
             var data = [];
@@ -265,7 +272,7 @@ define([
                 data.push({
                     // color : 'rgb(192, 128, 0)',
                     data : source.samples,
-                    label : key,
+                    label : "hallO",
                     lines : {
                         show : true
                     },
@@ -276,23 +283,24 @@ define([
                         show : false
                     },
                     shadowSize : 0,
-                    yaxis: i++,
+                    yaxis : i++,
                 });
             }
 
             self.flotData(data);
 
             setTimeout(function() {
-                self.update();
+                self.update(id);
             }, 100);
         }
 
-        self.update();
+        self.update(++self.updateId);
     }
 
     ViewModel.prototype.dispose = function() {
         console.log("disposing pal");
         this.propertySampler.stop();
+        this.updateId++;
     }
 
     // Return component definition