Tryst::Dnd
Class methods
@api private - the real implementation App#register_drop_target is reopened to call, once this shard is required. Resolves widget_path to a real Tk_Window (Tk_MainWindow then Tk_NameToWindow) and forces it to exist (Tk_MakeWindowExist - a window that has never been mapped has no real native handle yet for the platform layer to attach to) before calling straight through to the platform's own teek_register_drop_target.