The UI command seems to be missing, I remember being able to control or remove it completely before the latest functionality rework, but I can’t even find the text line with advanced interface options addon (/console autoOpenLootHistory)
Really, do something about it because it is annoying.
We have a regular basic loot window
then the boss drop indicator which also lists everything
add in loot history window /loot
and on top of everything we get roll buttons for each individual piece
It is terrible. Even my chat gets flooded with loot information.