How to activate Aoe?

[Amigurumi]

How to activate firebolt Aoe?

Hello!

I was looking in the ability editor, when I saw that the ability Firebolt (don't know how it's called) has an aoe.
Well, I was surprised, and tested it. But my unit didn't make any splash damage with this spell.

So how can I activate this splash?

[EDIT]
I just see, that the Thread name I've chosen, sounds very noobish -.-

 

[Freyleyes]

I am not sure, but it might be an error by blizzard or an unfinished ability. Not sure, but that is what I think.