Fragment Count Statics icon in Graphics Anaylzer is not enabled. How can I solve this?

Hi, I am trying to measure the fragment counts so I referred the User Guide of "Analyzing the fragment count".

It is just written that in order to enable the fragment count, just click the icon. 

But for some reason, the icon is not enabled in my program so I am having difficulty with this.

Other icons work well, but only the fragment count icon is not enabled. 

How can I make fragment count icon enabled?