Originally Posted by
Kelrugem
Yes, click "Add spell class" :) Do not hang up on the name of that, a better name for that would be "Add actions (class)" in that situation but a spell class is exactly doing what one needs for such actions, too :) There you can then add spells and actions like the ones from healing potions :) (there are a lot of options to define because of spells, you can ignore them for consumables :) )
When you added a spell/action there, then right-click on that for adding the heal button :)
PS: Pro-(?)-tip: Or add a weapon with a damage die same as for the heal die and add [HEAL] to the weapon's name :) Then this weapon will always heal :D But that is a very uncommon way to do that :D (and probably not an intended feature, just something one learns when one writes extensions :D)