This setting seems simply to be broken. It doesn't do what it claims to do. When DOSbox crashes and this setting is set to true, the debug window disappears instantly. Easily reproducable - get DOSbox to crash somehow. Like, set oplmode=none, go to Simcity 2000 setup (install.exe), select music source as 'Sound Blaster', wait for it to say it can't detect it, then click 'continue'. DOSbox crashes, debug window just disappears before you can read it.