WPF App With Identifier First Enabled Returns Script Error When Editing Email "Object doesn't support property or method initCustomEvent" in Auth0

When enabling Identifier First in the Auth0 Dashboard and performing a login event with a Windows Presentation Foundation (WPF) application, an error returns when a user attempts to edit the email address they initially entered. This occurs because the Auth0 WPF Software Development Kit (SDK) uses Microsoft Internet Explorer as the default browser, which lacks the enhancements necessary for newer Auth0 features. Using the Edge Chromium browser instead of Internet Explorer resolves the issue. When this failure occurs, Auth0 generates the following error message:

Object doesn't support property or method 'initCustomEvent'

• Auth0
• Windows Presentation Foundation (WPF) Application
• Software Development Kit (SDK)
• Identifier First

The error is likely caused by running the Auth0 WPF SDK as an Administrator, which uses Microsoft Internet Explorer as the default browser. This browser is quite old and missing a number of enhancements necessary for newer Auth0 features, such as the Identifier First flow. This is a known limitation with the WebView components provided by Microsoft.

How is the WPF application script error resolved?

To resolve this issue, refer to this knowledge solution How to Use the Auth0 oidcClient.WinForms SDK with Edge Chromium / WebView2, which provides a workaround to use the Edge Chromium browser instead of Internet Explorer.