Have this exact same problem and it drives me nuts. Hard to find anything. Would love to try an alchemy build but the craptasticness of the sort not working in the inventory has put me off from doing so. Things really need persistent text labels when you have this many items. I know it takes up more space but the current inventory system is a nightmare, for potions especially. Also, don't quite understand what's so hard to make the potions and decoctions sort by alphabetical order. At least that way if I know the name of the potion I at least know where to start in the inventory to find it if it's alphabetical. Right now I can't find anything because it's just a god awful mess with no discernible logic to how it's sorted.
