diff --git a/ext/fg/js/frontend-initialize.js b/ext/fg/js/frontend-initialize.js
index 7f70d9c4..352c6bd9 100644
--- a/ext/fg/js/frontend-initialize.js
+++ b/ext/fg/js/frontend-initialize.js
@@ -48,8 +48,10 @@ async function main() {
         const {popupId, frameId} = await rootPopupInformationPromise;
 
         popup = new PopupProxy(popupId, 0, null, frameId, url);
+        await popup.prepare();
     } else if (proxy) {
         popup = new PopupProxy(null, depth + 1, id, parentFrameId, url);
+        await popup.prepare();
     } else {
         const popupHost = new PopupProxyHost();
         await popupHost.prepare();
diff --git a/ext/fg/js/popup-proxy.js b/ext/fg/js/popup-proxy.js
index 242da04c..8693ef17 100644
--- a/ext/fg/js/popup-proxy.js
+++ b/ext/fg/js/popup-proxy.js
@@ -25,7 +25,6 @@ class PopupProxy {
         this._parentId = parentId;
         this._parentFrameId = parentFrameId;
         this._id = id;
-        this._idPromise = null;
         this._depth = depth;
         this._url = url;
         this._apiSender = new FrontendApiSender();
@@ -57,6 +56,11 @@ class PopupProxy {
 
     // Public functions
 
+    async prepare() {
+        const {id} = await this._invokeHostApi('getOrCreatePopup', {id: this._id, parentId: this._parentId});
+        this._id = id;
+    }
+
     isProxy() {
         return true;
     }
@@ -66,33 +70,22 @@ class PopupProxy {
     }
 
     async setOptions(options) {
-        const id = await this._getPopupId();
-        return await this._invokeHostApi('setOptions', {id, options});
+        return await this._invokeHostApi('setOptions', {id: this._id, options});
     }
 
     hide(changeFocus) {
-        if (this._id === null) {
-            return;
-        }
         this._invokeHostApi('hide', {id: this._id, changeFocus});
     }
 
     async isVisible() {
-        const id = await this._getPopupId();
-        return await this._invokeHostApi('isVisible', {id});
+        return await this._invokeHostApi('isVisible', {id: this._id});
     }
 
     setVisibleOverride(visible) {
-        if (this._id === null) {
-            return;
-        }
         this._invokeHostApi('setVisibleOverride', {id: this._id, visible});
     }
 
     async containsPoint(x, y) {
-        if (this._id === null) {
-            return false;
-        }
         if (this._depth === 0) {
             [x, y] = await PopupProxy._convertIframePointToRootPagePoint(x, y);
         }
@@ -100,30 +93,24 @@ class PopupProxy {
     }
 
     async showContent(elementRect, writingMode, type=null, details=null) {
-        const id = await this._getPopupId();
         let {x, y, width, height} = elementRect;
         if (this._depth === 0) {
             [x, y] = await PopupProxy._convertIframePointToRootPagePoint(x, y);
         }
         elementRect = {x, y, width, height};
-        return await this._invokeHostApi('showContent', {id, elementRect, writingMode, type, details});
+        return await this._invokeHostApi('showContent', {id: this._id, elementRect, writingMode, type, details});
     }
 
     async setCustomCss(css) {
-        const id = await this._getPopupId();
-        return await this._invokeHostApi('setCustomCss', {id, css});
+        return await this._invokeHostApi('setCustomCss', {id: this._id, css});
     }
 
     clearAutoPlayTimer() {
-        if (this._id === null) {
-            return;
-        }
         this._invokeHostApi('clearAutoPlayTimer', {id: this._id});
     }
 
     async setContentScale(scale) {
-        const id = await this._getPopupId();
-        this._invokeHostApi('setContentScale', {id, scale});
+        this._invokeHostApi('setContentScale', {id: this._id, scale});
     }
 
     // Window message handlers
@@ -153,19 +140,6 @@ class PopupProxy {
 
     // Private
 
-    _getPopupId() {
-        if (this._idPromise === null) {
-            this._idPromise = this._getPopupIdAsync();
-        }
-        return this._idPromise;
-    }
-
-    async _getPopupIdAsync() {
-        const {id} = await this._invokeHostApi('getOrCreatePopup', {id: this._id, parentId: this._parentId});
-        this._id = id;
-        return id;
-    }
-
     _invokeHostApi(action, params={}) {
         if (typeof this._parentFrameId !== 'number') {
             return Promise.reject(new Error('Invalid frame'));