code: public static void resetFocus (Stage stage) {
  		if (focusedWidget != null) focusedWidget.focusLost();
  		if (stage != null) stage.setKeyboardFocus(null);
  		focusedWidget = null;
  	}
docs: Takes focus from current focused widget (if any), and sets current focused widget to null. If widgets owns
  keyboard focus {@link #resetFocus(Stage, Actor)} should be always preferred.
  @param stage if passed stage is not null then stage keyboard focus will be set to null