I'm probably not being very clear, but I think I got it in the end.
On the rep frame I have OnShow:
Code:
kgPanels:FetchFrame("Character BG"):Hide()
kgPanels:FetchFrame("Character linesBR"):Hide()
kgPanels:FetchFrame("Character linesTL"):Hide()
and OnHide:
Code:
kgPanels:FetchFrame("Character BG"):Show()
kgPanels:FetchFrame("Character linesBR"):Show()
kgPanels:FetchFrame("Character linesTL"):Show()
(those are the 3 frames I made and parented to the Character panel). I think what was confusing me was the fact that when you open the reputation tab then close the panel outright, the command to show the character kgpanels is immediately superseded by them being parented to a panel you shut at the same time, so they effectively hide too.