Please describe the problem:
It seems that if you have a dual screen setup (separated screens, with xinerama disabled) if you have the pointer and you are using the second monitor the inactivity triggers anyway just like if you weren't working on the second monitor: this can be quite annoying considering it triggers the screensaver/screen power off and removes temporary gamma changes.
(tried with an nvidia card)

Steps to reproduce:
1. Setup a separated xscreen dual screen enviroment from nvidia-settings, keep xinerama disabled and save xorg.conf from the nvidia-settings application
2. Enable inactivity detection in gnome-screensaver and maybe select also a screensaver
3. restart x server to make the configuration active
4. login in
5. start working in the second monitor
6. eventually the screen saver will kick in during the work


Actual results:
The screensaver starts in both screen even if you were working after the "dissolvence" like effect. in any case it seems gnome isn't noticing that the computer isn't idle on the second monitor

Expected results:
That i don't get a screensaver/powered off screen while i'm working on my second monitor with either mouse or keyboard

Does this happen every time?
yes 100% of times

Other information: