If both hotbars 1-2 are full, Skills added by Polymorph do not appear automatically on your hotbar. This is another casualty of "hey let's have every single ****ing item you pick up get auto-added to the hotbar for no good reason at all" syndrome.
This shouldn't be happening at all if the UI had been coded so that the added skills temporarily replaced the ones you cast to get those skills in the first place.
