Since buying this 27″ iMac and adding a second external monitor, I am rapidly coming to the conclusion that Apple simply can’t have tested multiple monitor setups under Mavericks.
My reasoning behind this is that the behaviour of Mavericks on a 27″ iMac with a 24″ 1920×1080 external monitor attached seems to be completely random! Let me give you the evidence:
Case 1 – Any monitor will do. You would assume that when launching an application it will do one of two things. Firstly, it will try to open itself on the monitor it was last using, thus if I had Firefox open on Monitor 2, then when I lunch it again it will open on monitor 2 again. Secondly, it will observe whatever you have configured it for in the Dock. E.g. if I specify in the Dock that Firefox should use Desktop 1 then it should do just that. So far. my experience has been that the monitor on which an application opens is COMPLETELY RANDOM! Most days Firefox will open on the iMac, but about 30% of the time it will open on the external monitor for no reason that I can fathom. It’s not just Firefox, it’s 1Password, Readkit, Jump Desktop, you name it.
Case 2 – Window placement optional. Often when I open an application it opens with only half the window visible, i.e. half the window is off the edge of the screen. Even though when the application was last used the whole of its window was visible, next time around Mavericks decides that it’ll position the window half way off the screen!
Case 3 – Size is not important. Again, why is it so difficult for Mavericks to remember what size a window was when it was last open? I frequently find when launching an app that the new window is a tiny rectangle on the screen, rather than the size it was when I was last using it.
Case 4 – Out of sight, out of mind. Mavericks seems to have no idea where the boundaries of the screen are. I opened iFFmpeg only to find that its window opened completely off the screen. I could see it in Mission Control but no way could I get the iFFmpeg window on to a monitor where I could interact with it. Quitting the app and restarting it didn’t help and in the end all I could do was to reboot the iMac.
Case 5 – Sleep… all change. I have all my windows arranged across the two monitors and everything is finally how I want it. I step away for a while and Mavericks puts my iMac to sleep. On waking the machine, some windows have been minimized to just a title bar! Only way to rectify the issue is to quit the app and start again.
My guess is that Apple changed the rules surrounding multiple monitors and maybe didn’t tell the developers because the way Mavericks handles windows across two screen seems to be completely random!