Project structure: BaseElements folder; Clearer separation between internal and public classes, and between WPF and (soon to come) WinForms classes.
Show messagebox (WinForms) when clicking submit button.
Let Class property return string instead of Type to enable compatibility with Win32.
Let NativeParent/Children properties return object instead of FrameworkElement to enable compatibility with Win32.
Removed FrameworkElement constraint on IRegisteredElement to allow Win32 registrations.
Moved WPF types into WPF namespace to distinguish it from future Win32 controls.
Pluginable element factory. Support so far for WPF.
Move types to separate file in correct folders.
Basic support for Win32 controls. Goal is to handle message boxes opened from a WPF application.
Let FindFirstChild retry a few times.