how to equip elemental storm?

Hi, i made the ascendancy yesterday and i level up the two passives to get to elemental storm but now i dont know how to use it. It appears with the others abilities but i cant do right click and assign it to any key like the others.
Do i need anything else or it´s a bug?
https://imgur.com/GGEZPUZ

Elemental Storm is a triggered (crit) skill, and like other skills triggered by CoC for example, you can improve it with support gems in the skill tab, but you cannot bind it to a key to cast it directly.