screensaver unlock dialog window is not visible in clone mode

[DarkKnight BrightWarrior <bindasbeast gmail com>]

Hi,
 
Environment:
I am using CentOS 5.3 operating system. I upgraded xorg of centos to 7.3.
I am using intel 945 GM board. My xorg server version is 1.4.2 and inetl driver version 2.4.3.

gnome-screensaver version is 2.16.1-8.el5.
 
Problem:
I connected another system of same hardware using VGA output. Now I can see clone of my system on secondary display.
I enabled screensaver with 1 minute period and also enabled locking feature using gnome-screensaver-preferences.
After 1 minute screensaver appeared on both primary and secondary displays. But when I move mouse or press any key, Screen saver unlock dialog is not appearing.
But when I type password, I am able to comeout of screensaver. So Screensver unlock dialog is there but it is not visible.
When I remove secondary display, I mean when I am in single display mode screen saver unlock dialog is visible and working fine.
So what could be the problem that causing screensaver unlock dialog window to appear/visible in clone/extended monitor mode.
 
Please help.
 
Thanks