Sushant,

Apologies if you already ruled it out; however, is it possible that the panel is collapsed?  You are using the default global (domain) account so it will have the necessary permissions.  Even if it didn't, they would be greyed out and not missing altogether.  If you look halfway along the edge there is a subtle border that you can either:

1) Drag (double arrows once it has focus)

2) Expand (or collapse) by clicking on the "handle" half way down the edge

If not, then you can always use the naviseccli command:

ntp -set