code: public VisDialog show (Stage stage, Action action) {
  		clearActions();
  		removeCaptureListener(ignoreTouchDown);
  
  		previousKeyboardFocus = null;
  		Actor actor = stage.getKeyboardFocus();
  		if (actor != null && !actor.isDescendantOf(this)) previousKeyboardFocus = actor;
  
  		previousScrollFocus = null;
  		actor = stage.getScrollFocus();
  		if (actor != null && !actor.isDescendantOf(this)) previousScrollFocus = actor;
  
  		pack();
  		stage.addActor(this);
  		stage.setKeyboardFocus(this);
  		stage.setScrollFocus(this);
  		if (action != null) addAction(action);
  
  		return this;
  	}
docs: {@link #pack() Packs} the dialog and adds it to the stage with custom action which can be null for instant show