Reading Ajahn Chah, he mentions that the Buddha "stopped thinking". How is this to be understood in the Theravada framework? I am still very new to Pali terms, abhidammma and commentary and so on, and often the original term (in this case) has not been provided. Any insights, suttas, abidhamma, commentary passages that would help me understand would be greatly appreciated. I want to deepen my understanding of the Theravada philosophical framework.
My initial thoughts would be that because he no longer clings to the Khandhas, no Sankharas arise, and yet he does not wink out of existance at the moment of Awakening, because we say that there is Nibbana "with remainder". Why is there no thinking then?

