diff --git a/subprojects/extensions-app/js/main.js b/subprojects/extensions-app/js/main.js
index 382637c74..005d1ddc6 100644
--- a/subprojects/extensions-app/js/main.js
+++ b/subprojects/extensions-app/js/main.js
@@ -15,6 +15,7 @@ const { ExtensionState, ExtensionType } = ExtensionUtils;
 const GnomeShellIface = loadInterfaceXML('org.gnome.Shell.Extensions');
 const GnomeShellProxy = Gio.DBusProxy.makeProxyWrapper(GnomeShellIface);
 
+Gio._promisify(Gio.DBusConnection.prototype, 'call', 'call_finish');
 Gio._promisify(Shew.WindowExporter.prototype, 'export', 'export_finish');
 
 function loadInterfaceXML(iface) {