Problem 44364. Is this a valid Tic Tac Toe State?

The bug with deleting comments on problems or solutions appears to be longstanding. See https://au.mathworks.com/matlabcentral/cody/problems/43708

Thanks for the link, David Verrelli. I seem to remember that the "Delete" button did work in the not-too-distant-past (a few months ago), but maybe I'm misremembering things. However, to be honest, I don't mind this bug as much because I think it's a good thing that a comment can't be deleted when it has already received replies; otherwise a thread of comments would become unreadable. It's only when an erroneous comment of mine hasn't received any replies yet and the "Delete" button turns out to be non-functional that I experience a slight "Aaargghh!" moment, because the presence of the "Delete" button created different expectations. :-) But I don't really mind leaving my erroneous comment up and correcting myself in a new comment, as I did above.

Yurenchu, I agree that if a comment has received replies it's generally best not to delete it.