Around line 182, you should see this:
AUTOGAIN_HOVERALERTS_SWITCH = 5 # The ID of the switch used to turn the
# autogain feature on and off. If you never
# want to use it, set this to 0.
So, if you never want to use it, set it to 0. If you want to use it sometimes, set it to any integer. Then you can control it by turning the in-game switch with that ID on or off.
There is currently no way to have it on all the time but only display for some items and not others.