ugh

public/index.php

@@ -264,7 +264,13 @@ if (isset($_GET["embed"])) {
     ?>
     <script nonce="<?php echo $SECURE_NONCE; ?>">
         window.addEventListener("load", function () {
-            parent.window.postMessage(document.documentElement.scrollHeight + "px", "*");
+            // https://stackoverflow.com/questions/1145850/how-to-get-height-of-entire-document-with-javascript
+            var body = document.body,
+                    html = document.documentElement;
+
+            var height = Math.max(body.scrollHeight, body.offsetHeight,
+                    html.clientHeight, html.scrollHeight, html.offsetHeight);
+            parent.window.postMessage(height + "px", "*");
         });
     </script>
     <?php