Can you describe Kakasaheb Dixit's vision of Vitthal and how Sai Baba confirmed it?

Certainly. As detailed in Chapter 4, Kakasaheb Dixit experienced a vision of Lord Vitthal during his morning meditation. When he later went for Sai Baba's darshan, Baba surprised him by asking if 'Vitthal Patil' had come, referring to the vision. Baba playfully advised him to 'nail him down and make him steady,' as Vitthal is a 'big runaway.' The confirmation of this vision was further solidified that afternoon when a seller arrived with pictures of Vitthal of Pandharpur. The image in the pictures exactly matched the form Dixit had seen in his meditation, prompting him to purchase one and install it for worship, amazed by Baba's words.