There is a field in gameplay interface that pastes that green thing there when it's in use. If you remove that, you don't see it in the game. Find it yourself.
But I fail to see why is it important o.o
"Channel" It's a Hero abilit by default.
You also should check Options - Visible to true, Disables other Abilities false, and make it instant (no target).
And look up some Channel tutorials (use search)
I do know this - xenforo dropped the ball by not keeping the vbulletin reputation comments as a feature. The loss of the Reputation comments data when we switched to Xenforo really was the death knell for the site when it came to all the users that left. I know I missed it so much and I got way less interested in the site when that feature was gone and I run the site.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory