There was a bug in KMines: the program was freezing in a custom game if you chose to put in the field so many mines that there was not at least 9 free positions. Now, it's working.

New to avoid trivial games, KMines now constrains the user to let at least 10 (-> one more than 9) positions free.

Note: I'm not sure it's a good idea to avoid to put mines on neighbor positions to the start position... To discuss...