Kbox nano fire twice to fire

[paulbot]

Got in a Kbox Nano the other day, liking it's size better than the Kbox Mini I've been using. But to fire it, I have to hit the fire button twice, and can't seem to find any instructions how to turn that off. Is this a standard feature of the Nano?

 

[paulbot]

Well it turned out this is a clone, so no surprise it acts weird