fix: empty gadget content on refresh (pre-slot)

js/plugins/renderjs/renderjs.js

@@ -115,7 +115,7 @@ var RenderJs = (function () {
             // async
             if (async) {
               async(data, function(markup){
-                gadget.empty().append(markup);
+                gadget.append(markup);
                 if (callback) {
                   callback(self);
                 }