Material design icon in `button` node

Believe me when I say I am not doing this to annoy anyone.

I want to put this on a button as the "icon".

<i class="material-icons"> repeat_one </i>

Obviously I can't just put that in the icon field.

My brain has failed me again in working out how to do it.


Ok, I'll retract that.

Seems I can. But in the label field rather than the icon one.