I've done Kaon HM with a tank and myself as DPS with 2 healers comps.

Ingame Ctrl-Shift-F shows you FPS in the bottom-left corner...would that be enough?

Around 4:45 it really looks as clicking. To above poster, I didn't want to come off as a douche, but in hindsight it kinda did. I'm doubting now you are clicking, sorry OP!

Use keybinds.