Little more context: I have the same issue and, like Gareth, am also using Ubuntu on Mac hardware (Macbook Pro in my case). That means the external monitor connects via a Thunderbolt port.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1510021 Title: After upgrade from vivid to wily external monitor has only limited resolutions To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1510021/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
