[Fizzlemizz]

From DUF:

	if (event == "PET_BATTLE_OPENING_START" and self.unit ~= "target") then
		if DUF_Settings[DUF_INDEX].PetBattleHide then
			self.PetBattleHidden = true
			RegisterUnitWatch(self, true)
			RegisterStateDriver(self, "visibility", "[petbattle] hide; default")
		end
	end

if (event == "PET_BATTLE_CLOSE") then
		if (self.PetBattleHidden) then
			UnregisterStateDriver(self, "visibility")
			UnregisterUnitWatch(self)
			self.PetBattleHidden = nil
			self:Show();
			return
		end
...

DUF is over complicated in some things but this should give the context for pet battle/unit frame interaction.