removed ngClasses and used ngRemove in the appropriate places

panes/model.html

@@ -1,6 +1,6 @@
 <div ng-controller="ModelCtrl">
   <h2>Model Tree</h2>
-  <div ng-class="{hidden: roots.length <= 1}">
+  <div ng-hide="roots.length <= 1">
     <label for="select-root">Root <select id="select-root" ng-options="p.value as p.label for p in roots" ng-model="selectedRoot"></select></label>
   </div>
   <pre>

panes/perf.html

@@ -10,14 +10,14 @@
     </label>
   </form>
 
-  <div ng-class="{hidden: !enable}" class="row-fluid">
+  <div ng-hide="!enable" class="row-fluid">
     <div class="span6">
       <h3>Watch Tree</h3>
       <div class="well well-top" style="height: 400px; overflow-y: auto;">
         <bat-watcher-tree val="trees[selectedRoot]" inspect="inspect"></bat-watcher-tree>
       </div>
       <div class="well well-bottom">
-        <label for="select-root" ng-class="{hidden: roots.length <= 1}">Root 
+        <label for="select-root" ng-hide="roots.length <= 1">Root
           <select id="select-root" ng-options="p.value as p.label for p in roots" ng-model="selectedRoot"></select>
         </label>
       </div>