Ok, so my question is, action slot 121 is the extra slot, but we can't use PlaceAction to actually put anything there, it seems the server on it's side will put an action for you then trigger the UPDATE_EXTRA_ACTIONBAR event to animate show(or hide) the frame and let you click that button.
You can also force it to show using:
Code:
/run local f=ExtraActionBarFrame f:Show() f.outro:Stop() f.intro:Play()
Then to hide with just calling the normal event:
Code:
/run ExtraActionBar_OnEvent(ExtraActionBarFrame,"UPDATE_EXTRA_ACTIONBAR")
But on fights like Yssera you can try put her spell there:
Code:
/run PickupSpell(106466) PlaceAction(121)
Or just the normal autoattack spell:
Code:
/run PickupSpell(6603) PlaceAction(121)
But none of these work at all, because the action on that slow is unavailable to our API, except GetActionInfo and such.
(Note it is hidden but will be shown if you pickup a spell, it autohides when it has no spell on itself. It's instantly tainted if you try to edit the attributes trough commands like setting the isExtra value or such, makes the button totally unusable.)