diff --git a/label_studio/templates/setup.html b/label_studio/templates/setup.html
index b3e93c1d19cb..ebe61a25a71a 100644
--- a/label_studio/templates/setup.html
+++ b/label_studio/templates/setup.html
@@ -139,6 +139,7 @@ <h3>Output Completion Preview</h3>
 
 <script>
   var confirm_already_shown = false;
+  var iframeTimer = null;
 
   // process create request
   function process_request(result) {
@@ -287,10 +288,10 @@ <h3>Output Completion Preview</h3>
         iframe.show();
         // set height for iframe
         let obj = document.getElementById('render-editor');
-        obj.style.width = "100%";
 
         // wait until all images and resources from iframe loading
-        setTimeout(function() {
+        clearTimeout(iframeTimer);
+        iframeTimer = setTimeout(function() {
           obj.style.height = (obj.contentWindow.document.body.scrollHeight + 30) + 'px';
         }, 1000);