Can you describe the experience Kakasaheb Dixit had with Vitthal in Shirdi and how Sai Baba confirmed it?

Certainly. As detailed in Chapter 4, after his morning bath, Kakasaheb Dixit was in meditation when he received a vision of Vitthal. When he later went for Sai Baba's darshan, Baba surprised him by asking if "Vitthal Patil" had come. Baba playfully described Vitthal as a "big runaway" who needed to be nailed down and made steady, warning that he would escape if neglected even for a moment. The confirmation of this vision became even more profound that afternoon when a seller arrived with twenty-five pictures of Vitthal of Pandharpur. The form in the pictures exactly matched what Dixit had seen in his morning meditation. Astonished, Dixit recalled Baba's words, purchased one of the pictures with great love, and installed it for worship.