Performer grill cover question, Mine only has one strap!?!

I bought the official Weber grill cover(7152) for my Performer because it said it had strap to secure the grill. I back up to a preserved farm and get strong winds at times like yesterday with our little Nor'Easter.

When I went to put the cover on it only had one velcro strap to secure a leg. It was pretty useless in the wind even with putting some weights on the table.

Did I get a defective cover or was this by design?