Give the menu a transparent background

Hi,

I've posted this as a support ticket too, but when I get the solution I'll post it here for others. I just want to know how to make the menu background transparent!

Many thanks,

Dave.

Dear DavidBoggitt,
Thanks for contacing us and choosing our product!
We received your ticket and we will try to fix it asap.
So please wait! Many thanks!

*****
Best regards,
Long Do