What was Kakasaheb Dixit's experience with a vision of Vitthal, and how did Sai Baba confirm it?

According to Chapter 4, Kakasaheb Dixit had a vision of Lord Vitthal while sitting in meditation after his morning bath. When he later went for Sai Baba's darshan, Baba confirmed the experience by asking him, "Vitthal Patil had come, right? Did you meet him?" Baba further advised him to "nail him down and make him steady," warning that the vision could be lost through even a moment of neglect. The confirmation was further solidified when a seller arrived that afternoon with pictures of Vitthal, and one of them was an exact replica of the form Dixit had seen in his morning meditation. Amazed, Dixit bought the picture and installed it for worship.