I don't think that in my case this is a bug in Unity, but rather either in Glib, Xorg or in the NVIDIA driver. Running unity from the command line, and then observing the output while plugging in a monitor shows the following (abbreviated, lines marked with hashes have been added by me):
####### enabling external screen, setting it to be LeftOf and to be primary ###### Screen geometry changed: Monitor 0(primary) 1920x0x1440x900 Monitor 1 0x0x1920x1080 ####### switching back to single screen ###### Screen geometry changed: Monitor 0(primary) 0x0x1440x900 ####### enabling external screen, setting it to be LeftOf and to be primary ###### Screen geometry changed: Monitor 0(primary) 0x0x1920x1080 Monitor 1 1920x0x1440x900 The relevant code generating the output request that information directly from Glib, and as you can see, the first time round the external monitor (the one with the 1920x1080 resolution) is activated, the built-in monitor is reported to be the primary monitor and the arrangement is also wrong. The second time the external monitor gets activated, the information is actually correct. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/742544 Title: Launcher is shown on the wrong screen in some multi-monitor setups To manage notifications about this bug go to: https://bugs.launchpad.net/ayatana-design/+bug/742544/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
