How to mirror a first screen on the second and keep the highest resolution on the first screen? I've linked a second screen (1920x1080) to my iMac 27" (2560x1440) via HDMI (using a minidisplayport to HDMI adapter).
I want to mirror the first on the second but when I do this the first takes the resolution of the second which is lower. If instead I choose to extend the first on the second then the first keeps it resolution, but I can't access Mac OS X's interface from the second, only the windows I move to it.
The solution needs to work for 2 external screens.
In order to access Mac OS interface from another screen, go to System Preferences > Displays > Arrangement and take a look at the blue rectangles that represent the screens you currently have connected. One of them should have a white bar at the top, drag this bar to the screen that you want to access the OS interface from. That way you can keep the higher resolution, and access the interface. Unfortunately, if you mirror a display, it will take the lowest resolution because it cannot "create" the pixels required on the lower resolution screen in order to show a Mirrored display. If you want to keep the higher resolution, you have to extend the displays.