The changelog for v2.2.4 says the Raspberry Pi is officially supported, but I'm not seeing any native libs for linux-arm/arm64 in the NuGet packages. Am I misunderstanding what "Raspberry Pi 4 officially supported" means, or did the lib just not make it into the NuGet package?

Your MainWindow.xaml and MainWindow.xaml.cs files probably aren't being linked up properly at build time (and the same is likely true for App.xaml/App.xaml.cs depending on how you created them). xaml.cs files are usually partial classes to allow combining them with the xaml, so your MainWindows.xaml...