Sorry, to complement my comment. I'm running xfwm4 and xrandr says my big monitor IS the primary.
Screen 0: minimum 8 x 8, current 3840 x 1080, maximum 16384 x 16384 VGA-0 disconnected (normal left inverted right x axis y axis) LVDS-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 360mm x 200mm 1920x1080 59.94*+ 50.00 HDMI-0 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 598mm x 336mm 1920x1080 60.00*+ 59.94 50.00 60.05 60.00 50.04 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1425000 Title: Cannot set right monitor as primary in dual monitor configuration To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity-control-center/+bug/1425000/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs