Options for Sites under local internet is grade out via GPP (IE 10)

Hello,

I am trying to make changes via Group policy preference to IE 10,

I need to change options under, Internet options - security - local internet and sites,

But sites is grade out and f5 f6 etc is not a help.

Is this option not available to everyone and not possible via GPP or do I have some issues,

I have tried these changes via old way, they are getting applied to IE but not coming to effect.

Thanks