After some investigation, this looks to be a problem in the SDL version that dosbox uses internally (1.2). There is an ongoing effort to get dosbox working with SDL 2.0 [1], which has better multi monitor support as one of its main features and should improve the situation here.
[1] - http://www.vogons.org/viewtopic.php?t=34770 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/498513 Title: dosbox changes setting to "mirror" while using two displays To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dosbox/+bug/498513/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs