Hide visible elements while loading the slide app

www/slide/inner.html

@@ -6,6 +6,7 @@
     <style>
         .loading-hidden { display: none; }
         #editor1 { display: none; }
+        .cp-app-slide-modal-button { display: none; }
     </style>
 </head>
 <body class="cp-app-slide">