/** Creates a Root widget with custom input devices. If window is not null,
it is used to set the widget's initial geometry. */
Root(Resources &, Graphics::Window *, Input::Keyboard *, Input::Mouse *, Input::Touchscreen * = nullptr);
/** Creates a Root widget with custom input devices. If window is not null,
it is used to set the widget's initial geometry. */
Root(Resources &, Graphics::Window *, Input::Keyboard *, Input::Mouse *, Input::Touchscreen * = nullptr);