BagFilterTweak modifies the way the default backpack filters are handled slightly to make them play together nicer and let you filter multiple types of items into the same bag easier.

With the original filtering system, if you wanted to filter only a subcategory of some type of item into a bag (say, Apothecary crafting materials only), you couldn't also filter in items of a different main category (for instance, Weapons). Checking the Apothecary box would result in no weapons being put in the bag (even when Weapons was checked) because the weapons weren't of type Apothecary.

BagFilterTweak changes this so that checking any checkbox will put any items of that type or its subtypes into a bag, irregardless of whether it matches subtypes of another main type. It also makes it so that the main type doesn't need to be checked if a subtype item is checked.

Thus, if you check Crafting, all crafting components will go in a bag, while if you leave Crafting unchecked but check Apothecary, all Apothecary items will still go in that bag. Furthermore, if you check Apothecary and Weapons, but not Crafting, then you will get the desired result of: Weapons in bag, Apothecary items in bag, Everything else not in bag.

Rarity/Usability filters will still apply to all items.