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Originally Posted by Phanx This is fine, though unless other things are changing, a bit redundant for elements like Health where the element is already passed: OverrideUpdateHealth(self, event, unit, bar, min, max) Or would bar be going the way of event?

Using the old OverrideUpdateHealth as an example:

local PostUpdate = function(bar, unit, min, max)
end

For the health element the bar variable _is_ the element.

Originally Posted by Phanx Also, if Spawn will no longer accept a template, how will layouts indicate that a header should show pets? Currently that's done by passing the SecureGroupPetHeaderTemplate template...

The goal of this thread is really to catch corner cases such as that. That being said, I'm not entirely sure how I would want to solve it. There's two potential solutions to it that I can see instantly:
A: Add template as the argument after name, or at the end of the list. It should then also be used for the single-units.
B: Split the header part out of :Spawn and into :SpawnHeader. This would also require the arguments to be changed into: name, template, showParty, showRaid. It's also possible that name is removed all together, but that depends on how successful automatic naming will be.