First, I am not sure why I have to set the boss filter for each section instead of having it page wide like it used to be.
When I am in the Best of Slot section and then click on an item piece to see other pieces in that slot, since I set the filter I would think that all items displayed would only display the filtered items.
If you do not want this, then at least put the boss filter in the “Customize Gear” window, though that would be somewhat redundant.