I made some modifications and updated files.
Now you can flip the board (press "f"). You can see the list of moves in the file moves.txt.
Roland Chastain wrote:3° to understand why the engine doesn't see an obvious checkmate move (see engine\test7.bas).
I have found and corrected an error. The engine doesn't play the same move sequence : the problem seems to be solved.
I increased the search depth. The engine is a little longer to play, and seems to play better (see engine\test9.bas).
I haven't much time to play chess, because I spend too much time on my program. It's hard to make both the engine and the graphical interface. Look at the best programs that you can find on the web : you will never see a same person making a good engine and a good interface. As we say in France, "on ne peut pas être à la fois au four et au moulin".