diff --git a/ext/fg/js/frontend-initialize.js b/ext/fg/js/frontend-initialize.js
index bbb789cc..e674724e 100644
--- a/ext/fg/js/frontend-initialize.js
+++ b/ext/fg/js/frontend-initialize.js
@@ -31,7 +31,7 @@ async function main() {
         const popupHost = new PopupProxyHost();
         await popupHost.prepare();
 
-        popup = popupHost.getOrCreatePopup();
+        popup = popupHost.getOrCreatePopup(null, null, depth);
     }
 
     const frontend = new Frontend(popup, ignoreNodes);
diff --git a/ext/fg/js/popup-proxy-host.js b/ext/fg/js/popup-proxy-host.js
index 7d86aa67..49123ee1 100644
--- a/ext/fg/js/popup-proxy-host.js
+++ b/ext/fg/js/popup-proxy-host.js
@@ -47,7 +47,7 @@ class PopupProxyHost {
         ]));
     }
 
-    getOrCreatePopup(id=null, parentId=null) {
+    getOrCreatePopup(id=null, parentId=null, depth=null) {
         // Find by existing id
         if (id !== null) {
             const popup = this._popups.get(id);
@@ -76,7 +76,14 @@ class PopupProxyHost {
         }
 
         // Create new popup
-        const depth = (parent !== null ? parent.depth + 1 : 0);
+        if (parent !== null) {
+            if (depth !== null) {
+                throw new Error('Depth cannot be set when parent exists');
+            }
+            depth = parent.depth + 1;
+        } else if (depth === null) {
+            depth = 0;
+        }
         const popup = new Popup(id, depth, this._frameIdPromise);
         if (parent !== null) {
             popup.setParent(parent);