Comment 37 for bug 1209008

More details on todays behaviour:

After boot both screens come up, but sometimes seat-1 does appear, sometimes not and instead seat0 display extends to both monitors. Regardless of whether seat-1 appears or not, the initial position of mouse pointer of seat0 is offset BUT related to seat0's monitor. I think it is exactly in the middle of a big screen composed of BOTH monitors.

If, after boot, seat-1 does not appear, when I do ctrl-alt-f1 ctrl-alt-f7 at seat0 (which CanTTY=yes) then greeter at seat1 appears. BUT only until a screensaver kicks-in: then when I move a mouse at seat-1 (or even without it), instead of seat-1's greeter (no one is logged in at seat-1) a missing part of seat0's display appears - I have same folders at the desktop and they tend to appear in a part of the screen "covered" by seat-1's greeter. And then if I ctrl-alt-f1 ctrl-alt-f7 again, seat-1's greeter appears again.

The difference to yesterday and the day before is that I played with installing/uninstalling some packages.
The versions of packages of interest as of now are:
lightdm: 1.10.4-0ubuntu2
xserver-xorg-core: 2:1.15.1-0ubuntu2.6

I'm using Unity. I have no light-locker installed.

I must say that until yesterday I had rock-solid behaviour and fully functioning system except waking up from suspend. Then I perhaps messed something up with the installed packages. What packages other than lightdm and xserver-xorg-core should I check? Is it possible that lightdm 1.10.__4__ is causing problems?