IPv4 is not enable to configure under the policy

Hi all, I have 30d fortigate and using firmware version is v.5.2.1. and when i use Fortiexplorer In Policy&Object>Policy> IPv4 is there but it is not configurable on the right pane when selecting it.Right pane is empty. there is no any button active there like "Create New", "Edit" or "Delete" etc. How can I figure out this issue? Or is there setting I have to enable first? Thanks