App.xaml is the startup point for the application (build action is ApplicationDefinition). This opens a WinForm window, that eventually opens a WPF window (when a menu item is clicked). At this point, the application crashes, by the WPF window constructor, with
The calling thread must be STA, because many UI components require this.
I have tried using a Main method as the startup point with [STAThread] (and
setting the build action of App.xaml to Page), but it didn't help. App.ApplicationStartup has [STAThread].
Note that the project used to be just WinForms, and WPF was added later. Everything is done on the main UI thread.
Does anyone know of a possible solution? Hopefully that does not involve creating additional threads.
Thanks