Suggestion: locking an item in place in inventory to exclude it from sorting

I'd love to be able to lock certin items in my Bag, in my Chocobo, and in each of my retainers, so that those locked items are never moved by the sort function, but they are still otherwise manipulated normally (moving manually, taking them out, item search, batch move into retainer inventory etc).

Or if that's hard to implement, I'm perfectly fine with the ability to lock certain slots in these inventories, so that whatever is placed in those slots are excluded from sorting. An empty locked slot can't be filled by the system, items must be placed into locked slots manually, but newly received stackable items will be automatically stacked into a locked slot that already holds the same item.