What is the ruling on excessive movement during prayer?

Question:
He says: Honorable Shaykh, may Allah grant you success. Some people, while performing the congregational prayer, move around and clean their fingers. Some people say that while performing the congregational prayer, they move a lot and clean their fingers. Is it permissible for me to remind him during the prayer? And if reminding is permissible, how should it be done?

Answer:
I did not understand; he cleans his fingers? How does he clean his fingers? Does he crack his knuckles, or move his fingers? As for cleaning, I do not know how he cleans his fingers. But in any case, slight movement out of necessity is fine; slight movement out of necessity is not a problem. As for excessive movement without necessity, and if it is continuous without necessity, this invalidates the prayer. Yes.