don't use table display layout

frontend-js/src/main/js/minerva.js

@@ -290,9 +290,8 @@ function create(params) {
   }
   params.setServerConnector(ServerConnector);
   initGlobals(params);
-  params.getElement().style.display = "table";
-  params.getElement().innerHTML = "<div style='vertical-align:middle;display:table-cell;text-align: center'>"
-    + "<img src='resources/images/icons/ajax-loader.gif'/>" + "</div>";
+  params.getElement().innerHTML = "<div style='position:relative; width:100%;height:100%'>"
+    + "<img src='resources/images/icons/ajax-loader.gif' style='position:absolute;top:0;bottom:0;left:0;right:0;margin:auto;'/>" + "</div>";
 
   // make sure that we are logged in
   return ServerConnector.createSession().then(function () {