gnome-mastermind locks up and freezes on exit

[Mark S]

Running debian9 with xfce, there is an intermittent problem with the Gnome mastermind game. It doesn't happen every time (I'd guess about 1 in 5 times) but when I click quit or exit the program just locks up. If I right-click the title bar and try to use the close option a dialog appears telling me it's frozen, and with a button to force quit. This button usually works. But one time my whole system froze when trying to exit the game, forcing me to do a hard reboot on my PC. Maybe I shouldn't play games... ;-)