this issue has been logged as #2105.
A fix will be included in the next Wisej build.
We´ll inform you when it´s available.
Unfortunately there is a bug preventing Wisej from identifying the Program module (or something changed in .NET). Wisej checks if the class is static (or a module) checking IsSealed and IsAbstract. But VB.NET returns only IsSealed. It will be fixed in the next build. You can however add a method to Window1 and call it using the instance App.Window1.Method(). Or you can add it to the main page and call it using: App.MainPage.Method().