diff --git a/localrunner/visualizer/index.html b/localrunner/visualizer/index.html
index a034055..3233066 100644
--- a/localrunner/visualizer/index.html
+++ b/localrunner/visualizer/index.html
@@ -41,7 +41,7 @@
                         <div class="js-run toolbar__btn">
                             <i class="icon-play"></i>
                         </div>
-                        <div class="js-pause toolbar__btn btn_disabled">
+                        <div class="js-pause toolbar__btn hidden">
                             <i class="icon-pause"></i>
                         </div>
                         <div class="js-x1 toolbar__btn pressed" style="margin-left: 20px;">
diff --git a/localrunner/visualizer/js/events.js b/localrunner/visualizer/js/events.js
index 0a5a4ec..53c10fa 100644
--- a/localrunner/visualizer/js/events.js
+++ b/localrunner/visualizer/js/events.js
@@ -67,19 +67,19 @@ define(['conf', 'underscore'], function (conf, _) {
         });
 
         runButton.click(function () {
-            if ($(this).hasClass('btn_disabled')) return;
+            if ($(this).hasClass('hidden')) return;
             init.playWorld(function () {
                 pauseButton.click();
             });
-            pauseButton.removeClass('btn_disabled');
-            $(this).addClass('btn_disabled');
+            pauseButton.removeClass('hidden');
+            $(this).addClass('hidden');
         });
         pauseButton.click(function () {
-            if ($(this).hasClass('btn_disabled'))
+            if ($(this).hasClass('hidden'))
                 return;
             init.pauseWorld();
-            $(this).addClass('btn_disabled');
-            runButton.removeClass('btn_disabled');
+            $(this).addClass('hidden');
+            runButton.removeClass('hidden');
         });
 
         range.on('input', function () {