Hi, I can't play chess game, appear white window over the chess board and freeze the play
I can't play the chess game.
Over the the chess board appear small white window and freeze any movement that I want to do,
also I have no way to go back or forward or use the red dot at the left corner of the screen to close the window or quit the game.
What should I do to fix it?
iMac 2011
macOS Sierra
version 10.12.6