(Would also need fixing in admin-notifications)

I had very recently optimised the code to not generate an enormous Tempcode tree for the entire screen, given the memory issues we're having with the notification UI.
The code had in hackerish way accessed the array structure used for the Tempcode tree (during setting saving).
The correct fix was to clean up the code to not need to do that, having a proper data structure for what settings are active on the UI.