little bug?

[ccos]

i was just playing a game using the apple front end,
and my willy opponent managed saving it's skin
(silicone as it may be) by making a quite illegal move.

it had moved it's rook from it's original position and then moved it
back (h8-f8, f8-h8), which the rules of chess specify as a foregoing of 
the right
to castling with that rook. so it took me by surprise when it did just 
that.

anyway, i tried pulling some other illegal moves on it without much luck.
i think it's one of these players who likes to make up their own rules 
as they go along :)