So I don't know why, but the window where I can select numbers that I want from item stacks, e.g. buying how many items, dropping how many items, looting how many items, selling how many items, etc. can't be accessed. I don't know why, but just suddenly I can't seem to access it. It is more irritating than game-breaking, but I'd prefer to fix it as soon as possible.
Running PC with mods.
PS
I was thinking maybe a mod had something to do with this, but i haven't installed a new mod in ages! I've bashed and BOSSed and done all that stuff just in case, but can a mod do something like this in the first place?