Important to make "select/deselect all" operations work on all columns
simultaneously, even if they're offscreen. Unfortunately by the nature
of how the existing selection animation works, it is hard-tied to the
update loop, so we need to compensate.
It was causing selection/deselection of all mods to work improperly if a
select/deselect all operation was requested before the panel was
scrolled into view.
In general the schedule was an over-optimisation - the game-global set
of available mods shouldn't be changing so often as to warrant such an
aggressive debounce.
Bad sign when you can't follow your own code.
All of the various state changing methods were flattened into one
because it was too hard to follow what was calling what and why.