sopc builder ties the clcok enable of a costume block to 0!

I generate a block with SOPC Builder version 9.0. I look at the top level file that SOPC buildeer generates and I see the clock enable from top level is tied to zero! It is a real bummer! Anyway since we don't have any clock gating I tied the clock enable of my block to one! That fixed my problem but I am curious why it happens?