Comment 33 for bug 1300914

The behavior changed and I again checked several kernel versions and found an important difference:

* 46 shows lightdm greeter (password input) on internal and external monitor and after starting the session (login) the external monitor is deactivated but I can reactivate it (switch between internal/external/internal+external monitor) using the appropriate Fn+F key combination to make the session visible on the external monitor.

* 48, 49, 52, 51 shows lightdm greeter (password input) on internal and external screen but after starting the session (login) the external monitor stops working and Fn+F does not activate it again. Logging out again shows the lightdm greeter on both monitors but once in the session it is impossible to get the external monitor working except for logging out.

The only difference in behavior is the kernel version. At the moment only kernel 46 is usable.