The 1.4 list

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The current 1.4 definition of :Spawn is:
- :Spawn(unit, overrideName)
- :SpawnHeader(overrideName, template, showSolo, showParty, showRaid)

show{Solo,Party,Raid} is used to toggle visibility of the header. Setting showParty to true and showRaid to nil/false will actually hide the header, unlike the default behavior of the attributes.